When the parties have reciprocally declared their concordant intent, either expressly or impliedly, a contract shall be constituted.
If the parties agree on all the essential elements of the contract but have expressed no intent as to the non-essential elements, the contract shall be presumed to be constituted. In the absence of an agreement on the above-mentioned non-essential elements, the court shall decide them according to the nature of the affair.

A person who offers to make a contract shall be bound by his offer except at the time of offer he has excluded this obligation or except it may be presumed from the circumstances or from the nature of the affair that he did not intend to be bound.
Exposing goods for sale with their selling price shall be deemed to be an offer. However, the sending of pricelists is not deemed to be an offer.

An offer ceases to be binding if it is refused.

An offer made inter presentes ceases to be binding if it is not accepted at once.

An offer made inter absentes ceases to be binding if it is not accepted by the other party within the time during which notice of acceptance may be expected to arrive under ordinary circumstances.

If a period of time for the acceptance of the offer has been fixed, the offer ceases to be binding if it is not accepted within such period.

If an acceptance arrives late though it should usually arrive within a reasonable time by its transmitting manner, and this might be known to the offerer, the offerer should immediately notify the acceptor of such delay.
If the offerer delays the notice specified in the preceding paragraph, the acceptance shall be deemed to have arrived without delay.

An acceptance which arrives late, except under the circumstances in the preceding article, shall be deemed to be a new offer.
An acceptance with amplifications, limitations or other alterations shall be deemed to be a refusal of the original offer and the making of a new offer.

In cases where according to customs or owing to the nature of the affair, a notice of acceptance is not necessary, the contract shall be constituted when, within a reasonable time, there is a fact, which may be considered as an acceptance of the offer.
The provision of the preceding paragraph shall be mutatis mutandis applied when at the time of offer the offerer has waived notice of acceptance.

If a notice of withdrawing an offer arrives after the arrival of the offer itself, though it should usually arrive before or simultaneously with the arrival of the offer within a reasonable time by its transmitting manner, and this might be known to the other party, the other party so notified should notify the offerer immediately of such delay.
If such other party delays the notice specified in the preceding paragraph, the notice of withdrawing the offer shall be deemed to have arrived without delay.

The provisions of the preceding article shall apply mutatis mutandis to the withdrawal of acceptance.

When a public notice promises to reward the person for his performance of a particular act, it is a rewarding public notice. The promisor is bound to deliver the reward to the person who has performed the act.
When the act specified in the preceding paragraph has been successively performed by several persons, it is the person who has performed first acquires the claim for reward; when the act has been performed jointly by several persons or performed simultaneously by several persons respectively, it is these persons who acquire the claim for reward jointly.
In the preceding paragraph, if the promisor has delivered the reward in good faith to the person who has first notified his performance, the obligation of the promisor to deliver the reward shall be extinguished.
The provisions of the preceding three paragraphs shall apply mutatis mutandis to the person who has performed such act specified in the public notice without knowing of this notice.

If there is a specific right acquired because of the performance of an act in the preceding article, this right shall belong to the person who has performed the act, unless otherwise notified in the public notice.

When a promise of reward made by a public notice is withdrawn before the act is performed, the promisor is bound to compensate the person performing the act in good faith for the injury arising therefrom, unless the promisor can prove that the person could have never performed the act. The compensation shall not exceed the amount of the promised reward.
When there is a period of time fixed for the performance in the public notice, the promisor is presumed to waive his withdrawing right.

If a public notice promises to reward the person who has performed a particular act, notified within a certain period of time and has been evaluated as the best, it is a rewarding public notice for the best. The promisor is bound to deliver the reward in the completion of the evaluation.

The evaluation in the preceding article shall be proceeded by the person appointed in the public notice. If there is no any appointment in the public notice, it shall be proceed with the manner decided by the promisor.
The evaluation according to the provision of the preceding paragraph shall be binding on the promisor and the promisee.

If there are several persons evaluated as the best, unless otherwise notified in the public notice, these persons acquire the claim for reward jointly.

The provision of Article 164-1 shall apply mutatis mutandis to the rewarding public notice for the best.

If it is agreed between the parties that a contract shall be made in a certain definite form, the contract is presumed to be not constituted before the completion of such form.

If a contract is made for the obligations of the transferring, creation, or altering of rights over the real property, it shall be made in the notarization made by the notary public.
A contract not notarized according to the provision of the preceding paragraph could still be valid if the parties have agreed on the transferring, creation, or altering of rights over the real property and have completed the recordation.