legal ground
Article 492 of the Civil Code
The place where the acceptance takes effect is the place where the contract is established.
Where a contract is concluded in the form of a data message, the recipient's principal place of business is the place where the contract is established; If there is no main place of business, the domicile shall be the place where the contract is established. Unless otherwise agreed by the parties, such agreement shall prevail.
Article 493
Where the parties conclude a contract by contract, unless otherwise agreed by the parties, the place where the contract is finally signed, sealed or fingerprinted shall be the place where the contract is established.