Does the company registration number have to appear in an email signature?

Trading companies are subject to identification obligations in their documents and correspondence. The signature is the natural place to carry them in an email. Have the exact list applicable to your legal form validated by your counsel.

Are the notices the same for every email?

No. An internal operational exchange, commercial correspondence and an advertising communication do not call for the same obligations. In practice, many organisations adopt the broadest set so they do not have to sort messages.

Do the notices need translating for foreign correspondents?

The applicable notices are those of the country where the sending entity is registered, whatever the language of the message. A foreign subsidiary applies its own country's obligations.

Where should the notices sit in the signature?

At the foot of the block, in small type and light grey: readable without dominating. They must not compete visually with the name and contact details.

Mandatory legal notices in a business email

What information has to appear in a business email depending on legal form and activity: company identification, regulated professions, commercial communications.

“What has to be in an email signature?” has no universal answer. The obligations depend on your legal form, your sector and the nature of the message. Here is the framework for reasoning — to be validated by your counsel, who alone can qualify your situation.

This article describes a general framework, drawn from French law. It does not constitute legal advice. The exact list applicable to your company has to be established with your counsel.

The principle: making identification possible

The spirit of the texts is constant: whoever receives a communication from a company has to be able to identify who is writing to them, and find the corresponding legal entity.

That requirement flows from several sources — company law for documents and correspondence, consumer law for commercial communications, e-commerce law for online services. They overlap substantially, and the most complete set generally covers the others.

The common set for a trading company

For a French trading company, the elements usually carried in correspondence are:

the company name, as registered;
the legal form — SAS, SARL, SA;
the registration number in the trade and companies register, with the registry city;
the registered office address;
where applicable, the share capital.

The intra-community VAT number is added as soon as you invoice within the EU.

One line is enough to carry the essentials:

Example SAS, share capital €50,000 — RCS Paris 123 456 789 — 9 rue des Halles, 75001 Paris

Regulated professions

Some activities add their own obligations, generally set by their governing body or supervisory authority: lawyers, accountants, healthcare professionals, estate agents, insurance and banking intermediaries, among others.

The expected elements vary — bar or professional body, registration number, supervisory authority, professional licence number, warning notices. If you belong to a regulated profession, the applicable list comes from your governing body, not from a generic template.

The nature of the message matters

The same sender is not subject to the same requirements depending on what they send. An operational exchange with a supplier, a commercial proposal and an advertising communication fall under partially different regimes.

In theory, you could modulate. In practice, most organisations adopt the broadest set and apply it to everything: sorting messages by their legal nature is neither realistic nor risk-free.

That is also an argument for a centrally managed signature rather than one left to each person: the notice is present everywhere, or it is reliably present nowhere.

The case of groups

The notices follow the legal entity sending the message, not the group’s head office. A subsidiary has its own name, its own registration, its own address.

That requires one template per entity — it is in fact the first technical reason to multiply templates in a group, ahead of any brand question. The subject is covered in multi-brand signatures.

For foreign entities, the obligations of the country of registration apply, whatever the language of the message — see bilingual email signatures.

Where and how to place them

At the foot of the signature, below the contact details, in reduced type — 10 to 11 px — in light grey. Readable, but visually secondary: they must not compete with the name and phone number.

One or two lines is enough in most cases. If your notices block runs beyond four lines, check that everything is genuinely mandatory: the heaviest signatures often accumulate notices added out of caution and never removed.

Worth knowing: legal notices are among the elements that should be locked in the template. An employee rewriting their signature generally deletes them with no particular intention — simply because they do not know what they are for.

The point to watch: updates

A change of registered office, a capital increase, a change of legal form: those events make the notices inaccurate overnight.

Under manual management, correcting them assumes each person edits their signature. The completion rate is what it is, and you keep incorrect notices in circulation for months — which is worse than not having them.

With a centralised template, the correction is a single operation. It is the most direct argument with a legal department, and it complements the brand governance one well.

The confidentiality disclaimer, often confused with mandatory notices, follows a different logic: see confidentiality disclaimers.