Can I have a contract I signed annulled?

Error, and its limit

Error vitiates consent where it bears on the nature of the contract, on the object of the prestation, or on any essential element that determined the consent (article 1400).

The limit is sharp: inexcusable error is not a defect of consent. Someone who did not read what they were signing, when they could have, cannot rely on it.

That is what separates regret from legal error. Having paid too much is not an error under the Code; having been mistaken about what you were buying is.

Fraud: the manoeuvre, and the silence

Fraud is error provoked by the other party, or known to them. It vitiates consent wherever, without it, the party would not have contracted or would have contracted on different terms (article 1401).

The decisive words are few: fraud may result from silence or concealment. You need not have been lied to. Having a determining fact withheld by a party who knew it is enough.

That underpins many files: a seller who knew of a problem and said nothing, a partner who kept an existing commitment quiet.

Fear

Fear of serious injury to the person or property vitiates consent where it is induced by violence or threats from the other party or known to them (article 1402).

The apprehended injury may concern another person — a relative, for instance — and it is assessed according to the circumstances, taking account of the real situation of the person who signed.

On this ground, prescription runs only from the cessation of the violence or fear (article 2927).

Lesion: rarely available to adults

This is the most useful correction on the page. Many people believe an unbalanced contract can be annulled on that ground alone. It cannot.

Apart from cases expressly provided by law, lesion vitiates consent only for minors and adults under tutorship or a protection mandate (article 1405).

A capable adult who made a bad bargain has no claim in nullity on that basis. The ground must be found elsewhere: error, fraud, or a regime specific to the type of contract.

What you can ask for

A person whose consent was vitiated may seek nullity of the contract. In cases of fraud, fear or lesion, they may also seek damages (article 1407).

There is a third route, often the most practical: if you would rather the contract stood, you may seek a reduction of your obligation equivalent to the damages you could have claimed.

That helps where undoing the contract would cost more than correcting it — a property already occupied, a business already integrated.

What happens if nullity is granted

A contract that is annulled is deemed never to have existed, and each party is bound to restore to the other the prestations received (article 1422). So it is not a simple erasure: what was received has to go back, which is not always desirable or possible.

In lesion cases, the court may also maintain the contract whose nullity is sought, where the defendant offers a reduction of their claim or an equitable monetary supplement (article 1408).

Time matters, but differently

Prescription for an action in nullity runs from knowledge of the ground of nullity, or from the cessation of violence or fear (article 2927). An old contract is therefore not necessarily out of reach.

But continuing to perform after discovering the defect weakens your position. A contract affected by relative nullity is susceptible of confirmation (article 1420), and continuing to perform with knowledge of the defect can be read as exactly that. From discovery, stop acting as though nothing happened and put your position in writing.