E-signature: what the law (eIDAS) says, simply

In short

• An electronic signature has real legal value in Europe: it is the eIDAS regulation that frames it, with 3 levels (simple, advanced, qualified).
• All three are admissible in court; the qualified one additionally has the equivalence of a handwritten signature and reverses the burden of proof.
• In B2B (quotes, commercial contracts), simple or advanced is enough in the vast majority of cases.
• The real technical stake: an archived proof file (time-stamping, traceability), not the "level" itself.

The problem, concretely

"Will it hold up in front of a judge?" That is the first question when replacing the paper signature. The fear: that a client contests a contract signed online. The good news: the eIDAS framework makes the electronic signature perfectly valid, provided you choose the right level and keep the evidence.

The 3 eIDAS levels

• Simple (SES): ticking a box, signing in one click after receiving an email/SMS code. The lightest level of assurance, but admissible. It is the standard for e-commerce and most commercial contracts.
• Advanced (AES): the signer's identity verified and uniquely linked to the document, via a certificate. For higher stakes.
• Qualified (QES): an advanced signature created with a qualified device and a certificate issued by a qualified trust service provider (QTSP). It is the only level whose legal effect is equivalent to a handwritten signature (art. 25 eIDAS).

Which to choose? (the nuance that matters)

A practical rule, based on the risk of dispute: low to moderate risk and an unregulated contract (classic B2B) → simple or advanced, that is largely enough and far smoother for the signer. High risk or a contract subject to a mandatory written form (high amounts, regulated acts) → qualified. Over-sizing the level adds friction (heavy identity verification) without benefit: the right level is the one that matches your real risk.

The legal point to remember: the burden of proof

With a qualified signature, the burden of proof is reversed: if someone contests, it is up to them to prove the signature is invalid. With a simple or advanced signature, it is up to you to demonstrate consent, hence the importance of the proof file.

And technically, in your app

The most important thing is not the displayed level, but the proof file: time-stamping, traceability of the journey, archiving. APIs like Yousign (eIDAS, FR support, EU hosting) or Documenso (open-source, self-hostable) provide it. I plug the right level into your application, with document generation, a signing journey and status tracking via webhook (see the signature feature).

Sources

• eIDAS & legal value of the electronic signature
• Yousign · simple, advanced, qualified levels
• France Num · the electronic signature