Property law

In the unilateral promise to sell, one of the parties, the owner, undertakes to sell immediately, under determined conditions, to the other party, the beneficiary, if the latter exercises the option. The beneficiary has an exclusive option for a limited period of time. He/she is free to conclude the contract by exercising the option or not conclude it by letting the period expire.

The unilateral promise of sale is concluded as a result of a match between offer and acceptance. In the promise of fundamental elements of the future sale, the parties agree upon at least the property and the price. On the day that the promise is concluded, the owner must be able to proceed with the sale and the beneficiary able to exercise the option.

The unilateral promise of sale is therefore a contract requiring an agreement between the owner and the beneficiary, with an agreed option available to the latter. It differs from the sales offer, a unilateral act of will from the offeror. It also differs from the bilateral promise in which each party agree upon the future contract, with neither of them having an option.

is the promise of sale restricted to a particular format?



The unilateral promise of sale relative to a building, property law, a business, leasehold rights for all or part of a building or for companies listed under articles 728 and 1655 ter of the General Tax Code, must, under penalty of nullity, be established by a notarised deed or private deed recorded within ten days from the date of acceptance by the beneficiary.

It is the same for any sale incorporating the aforementioned promises which has not been subject to a notarised deed or private deed registered within ten days of its date.

a unilateral promise 

of sale by NOTARISED DEED?



The unilateral promise of sale is easier to draft than the provisional agreement, and has greater legal clarity. 

Aside from the usual benefits of the notarised deed, the notary, as a qualified professional, provides greater security. 


The notary must ensure to include:


  • The validity period of the promise;
  • The conditions of exercising the option;
  • The conditions of the promised sale (date of effect, price, general terms and conditions);
  • The conditions of notarised sales deed;
  • The technical diagnosis file;
  • The sanitary status of the building;
  • The possible earnest money;
  • The escrow;
  • The option of substitution;
  • the tax regime of the future sale.


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