Russia
Article 5. Customs in business practice. See also Mandatory Obligations
1. A custom in business practice is recognized to be a rule of behaviour not provided for by the legislation that has long developed and been in wide use in some business field regardless of whether or not it has been recorded in a document.
2. Business practice customs conflicting with the legislation or contract provisions that are binding on the parties to appropriate relations shall not be applied.
Article 6. Application of civil legislation by analogy. See also Mandatory Obligations Agreed Obliations
1. In the cases where relations specified by pts. 1 and 2 in article 2 of this Code are not directly regulated by the legislation or by the parties' agreement and there is no applicable business custom, civil legislation regulating similar relations (analogy of the statute) is applied to such relations unless this is contrary to their essence.
2. If it is impossible to use the statute analogy, the parties' rights and duties are determined proceeding from general principles and tenor of civil legislation (analogy of the law), as well as requirements of conscientious, reason and justice.
Article 10. Limits for the exercise of civil rights. See also Remedies
1. Citizens and legal persons are banned from actions undertaken exclusively with the intention of inflicting damage on other persons, as well as from the misuse of a right in any other form.
The use of civil rights for the purposes of setting bounds to competition, as well as the abuse of domination on the market are not permitted.
2. If the requirements specified in pt. 1 of this article are not observed, the court of law or court of arbitration can deny the person protecting the right belonging to him.
3. In the cases when the law makes protection of civil rights dependent on whether these rights have been exercised reasonably and conscientiously, reasonable actions and conscientious of participants in civil relations at law are presupposed.
Article 157. Transactions Concluded under Condition see also Termination Formations
1. A transaction shall be considered concluded under a condition suspensive if the parties have made the arising of rights and duties dependent upon a circumstance relative to which it is unknown whether this will ensue or not.
2. A transaction shall be considered concluded under a condition subsequent if the parties have made the termination of rights and duties dependent upon a circumstance relative to which it is unknown whether this will ensue or not.
3. If the ensuing of a condition is obstructed in bad faith by a party for which the ensuing of the condition is disadvantageous, the condition shall be deemed to have ensued.
If the ensuing of a condition is facilitated in bad faith by a party for which the ensuing of the condition is advantageous, the condition shall be deemed not to have ensued.
Article 421. Freedom of Contract see also Mandatory Obligations Agreed Obligations
1. Citizens and legal entities shall be free in concluding a contract.
Coercion to conclude a contract shall not be permitted except for instances when the duty to conclude a contract has been provided for by this Code, by a law, or by a voluntarily accepted obligation.
The parties may conclude a contract which is either provided for or is not provided for by a law or other legal acts.
The parties may conclude a contract which contains elements of various contracts provided for by a law or other legal acts (mixed contact). The rules on contracts whose elements are contained in a mixed contract shall apply in respective parts to the relations of the parties under a mixed contract unless it follows otherwise from the agreement of the parties or the essence of the mixed contract.
4. The conditions of a contract shall be determined at discretion of the parties except for instances when the content of the respective condition has been prescribed by a law or other legal acts (Article 422).
In instances when a condition of a contract has been provided for by a norm which applies insofar as not established otherwise by agreement of the parties (dispositive norm), the parties may by their agreement exclude the application thereof or establish a condition which differs from that provided therein. In the absence of such agreement, the condition of the contract shall be determined by the dispositive norm.
5. If a condition of a contract has not been determined by the parties or by a dispositive norm, the respective conditions shall be determined by the customs of business usage applicable to the relations of the parties.

