If no choice of law has been made by the parties to a contract, or the choice is not clear, then according to Art. 4. ECO one has to determine what the [...] of the contract is.Paying money to another party is a common feature of many contracts and for that reason is not in any way "characteristic". So the party receiving payment is therefore the one effecting a [...] of the contract. If the country of the party carrying out the [...] is known, one has to apply the law of that country to the contract.