No law sets sending hours for a commercial text message. The CNIL guidance page, updated on 10 June 2026, does set a precise framework in France: consent for consumers, and in every message the sender’s identity plus a simple way to refuse. Successful SMS prospecting starts with checking the numbers, runs in 6 steps and is steered with 4 indicators. The 4 message templates below are written for B2B, with one B2C case at the end of the series.
Check where the numbers come from and their status before any send
A file is built through direct collection, business card exchanges or a purchase from a list broker. In every case, running it through an HLR Lookup verification service removes dead numbers before you pay for them.
HLR (Home Location Register) queries the carrier’s network to find out whether a number is assigned to a subscriber and reachable. Most routers bill for a cancelled number, since the message goes out anyway. Removing those lines before sending lowers the cost of the wave and protects the sender’s reputation with carriers.
This step matters more for a purchased file than for an address book built by hand. A list seller rarely guarantees that the mobile numbers are fresh. Nor does the seller guarantee that people were told their number would be reused, although the CNIL asks you to make sure of it when data is acquired from third parties. A buyer who has not checked this point stays responsible for the sending.
An HLR status is valid at the minute of the query. A number that is active today can be cancelled in 6 months or reassigned to another subscriber, which justifies a new check before every large wave. HLR also says nothing about whether the owner wants to read or answer the message: out of 100 valid numbers, none guarantees a reply.
What does the law require before the first message goes out?
In France, B2C texts require prior consent. B2B prospecting can rest on legitimate interest if the message relates to the recipient’s profession and the person has been informed beforehand.
For private individuals, the CNIL, the French data protection authority, requires a positive action: a dedicated box that is not pre-ticked. Accepting the general terms is not enough. The existing-customer exception requires that a sale or a service has taken place and that the offer covers similar products or services. An account created on a website without a purchase does not count.
For professionals, the CNIL accepts legitimate interest when the subject of the approach relates to the profession of the person contacted. Its example: software offered to a company’s IT director. For example, offering that same software to the secretary of a law firm falls outside the framework. The person must also be told that their number may be used and be able to object simply and free of charge, including when the file was acquired from third parties.
The number of a company director or of a self-employed salesperson remains personal data. If you doubt the recipient’s status, treat them as a private individual and ask for their agreement. In every case, keep a record of where the number came from, when it was collected and what the person was told: that is what you will hand over in an inspection.
Two obligations apply in all cases: each message shows the identity of the organization sending it and offers a simple way to refuse the next ones. The STOP mention and its legal framework are covered in a dedicated article. A recipient can also report an unwanted text to 33700, a platform created in 2008 by the French authorities and the carriers. The principles of legal basis and information are the same as for email, as the article on GDPR applied to email marketing explains.
Breaches carry real penalties. In France, Article L. 34-5 of the postal and electronic communications code caps the administrative fine imposed by the consumer protection authority at €75,000 for an individual and €375,000 for a legal entity. The CNIL has its own power to sanction. In its decision of 25 June 2026 (no. 2026-1210 QPC), the Constitutional Council ruled this regime unconstitutional, because three authorities punish the same facts. Repeal is postponed to 31 October 2027. Until then, an authority can no longer pursue facts already pursued or sanctioned by another.
Build the campaign in 6 steps, from objective to first send
A campaign takes 6 steps, each with a deliverable you can check: an objective, segments, a text, a schedule, a display test and then a pilot batch.
- Set a single objective per wave: a 15-minute meeting, a reminder or a demo sign-up. Two requests in the same text split the replies.
- Segment by job function and by sector. A CFO at a small construction company and a logistics director do not share the same urgencies, so they do not get the same message.
- Write the text with the length in mind: 160 characters in the GSM alphabet, 70 as soon as one Unicode character appears. The details are in the article on the number of characters in an SMS.
- Schedule the sends and decide on the follow-ups in advance (see below).
- Send a test to 5 colleagues over 1 working day, on different carriers, to check how the sender name and the link display.
- Launch a pilot batch of 200 to 300 numbers before the rest: the first replies and the first “STOP” messages correct the next wave.
The sender does better with an alphanumeric name of 11 characters at most, the brand name, than with an unknown number. That name meets the identification obligation. On some routers it rules out a direct reply, so plan a callback number or a keyword in the text. Never send the wave from a French mobile line, meaning a number starting with 06 or 07: ARCEP, the French telecoms regulator, has barred these numbers from automated sending since 1 January 2023. The carrier can suspend the line.
Four SMS templates for a B2B prospect or a contact who has consented
A good text has a hook tied to the person’s job, a single request, the sender’s name and a way to refuse. Here are 4 templates to adapt, with the fields to replace in square brackets.
First B2B contact, with a link to the profession:
Hello [First name], Julie from [Company]. CFOs at small construction firms ask us how to chase unpaid invoices without sending letters. 10 minutes on Thursday to talk about it? STOP to XXXXX
After a call:
Hello Ms [Last name], Thomas from [Company]. Following our conversation this morning, we suggest Tuesday at 2 pm for a 15-minute demo. Reply “YES” to confirm. STOP to XXXXX
Follow-up after 7 days:
Hello [First name], we are following up on our message from last Thursday. If the topic is not relevant now, reply “NO” and we will not write to you again. [Company]. STOP to XXXXX
B2C with opt-in, sent only to a person who ticked the consent box:
[Brand]: thanks for signing up, Lea. You will receive 2 offers a month at most. Reply “YES” to confirm. STOP to XXXXX
The first template names a trade and a concrete problem: that link with the profession is what grounds legitimate interest in B2B. The last one relies on consent collected beforehand, and the article on opt-in SMS messages offers more wordings. Avoid an anonymous shortened link in a first contact: it looks like a phishing attempt and some carriers filter it.
Sending hours and cadence to adopt
No legal text sets hours for a commercial SMS. The af2m charter, revised on 1 March 2026, relaxes sending on Sundays and public holidays. In B2B, stay within office hours.
That French charter targets sending platforms first and remains a code of good conduct that does not settle B2B prospecting. A director who receives a message at 9:15 pm on a Friday does not read it the way they read one at 10:30 am on a Tuesday. For a professional target, test 2 slots (mid-morning and early afternoon) on two halves of the file for 2 weeks before fixing the schedule. First thing on Monday and after 4 pm on Friday are field hunches to check on your own file: no public study establishes them.
On cadence, a reasonable starting point in cold prospecting is 2 to 3 messages per contact over 30 days, adjusted to your unsubscribes: a first SMS, then follow-ups at 7 and 21 days. Beyond that, each unsubscribe weighs on the file. As soon as a recipient replies “NO” or “STOP”, they leave every sequence, including email and phone ones.
A sequence that combines call, SMS and email
SMS works best between two other channels: email sets the context, the call opens the discussion and the SMS confirms or follows up.
A 10-day sequence can run like this. A short email introduces the subject on day 1. The salesperson’s call follows 2 days later, with an SMS the same day if nobody picks up. The follow-up SMS goes out 4 days after that, 7 days in total, and a last email proposes a precise date at day 10. Alternating channels avoids three messages in the same half-day.
SMS fits well after a missed call or an unfinished exchange, like the second template above. For a relationship that is already established, it is worth comparing WhatsApp and SMS according to your audience and your contacts’ channel preference. The general arguments for the channel, such as reading speed, are detailed in the article on the reasons to do SMS marketing; choosing a router is covered by the page on business SMS.
How much should you budget without knowing your router’s rate?
The budget of a wave is calculated like this: valid numbers × SMS in the sequence × the router’s unit price. Numbers removed by HLR drop out of the calculation.
Take a hypothetical file of 5,000 numbers. If HLR verification removes 400, the wave covers 4,600 numbers. With a sequence of 3 SMS, the router bills 13,800 sends instead of 15,000: 1,200 sends avoided, or 1,200 times the unit price in your contract. That price varies with volume and supplier, and you read it on the quote. Add the cost of the HLR verification to the calculation.
The four figures that steer the campaign
Four indicators are enough. Two measure the base and the message (deliverability, replies), and two measure the result and the pressure applied (conversion, unsubscribes). The open rate cannot be measured reliably on an SMS.
| Indicator | Calculation | What it reveals |
|---|---|---|
| Deliverability | SMS delivered ÷ SMS sent | Quality of the base: a low rate points to HLR before any other adjustment |
| Reply rate | Replies ÷ SMS delivered | Relevance of the message and of its link with the job |
| Conversion | Meetings obtained ÷ SMS delivered | Effectiveness of the single request |
| Unsubscribe | “STOP” ÷ SMS delivered | Contact pressure too high or targeting too wide |
Always calculate on “delivered” SMS and not on raw sends: the unsubscribe rate, for example, reads as the number of “STOP” messages per 100 SMS delivered. With 92 meetings, the conversion rate is 2% on 4,600 valid numbers, against 1.84% if the denominator stays at 5,000. Set your own thresholds after the first 3 waves, about 90 days at one wave a month: no reliable public benchmark separates B2B from B2C on this channel.
Which mistakes make a campaign fail?
Failures come from an unverified file, a message with no link to the recipient’s job or a follow-up sent too soon.
Sending from a personal phone deprives you of statistics and exposes a private number. Forgetting the refusal mention makes the message non-compliant with CNIL rules. Buying a file without asking where the numbers came from or when they were collected means importing the seller’s risk. Mixing customers and prospects in the same file prevents you from applying the right legal basis to each: segment before the send, never after the first complaints.
Frequently asked questions
Can you send a commercial SMS to a professional without their consent?
Yes, if the subject of the message relates to their profession, they were told how their number would be used and they can object simply and free of charge. Otherwise, their consent is required.
What is the difference between a B2B file and a B2C file?
B2C requires prior consent. B2B rests on legitimate interest, provided there is a link with the profession. At the slightest doubt about the recipient’s status, apply the private-individual regime.
How many SMS follow-ups should you plan?
Two follow-ups at most over 30 days: one at 7 days and one at 21 days. After a “NO” or a “STOP”, the contact leaves every sequence, without waiting for the next wave.
Should you verify numbers before every campaign?
Yes, because the status of a number changes with cancellations and reassignments. A sample of 200 numbers run through HLR Lookup before the next wave shows within minutes how many lines to remove from your file.
