The law does not provide for a maximum duration binding a consumer to their supplier. In practice, suppliers generally offer supply contracts of indefinite duration, which can be terminated at any time, provided that the notice period laid down in the special or general conditions of the supply contract is respected.
In a fixed-term supply contract, all durations are theoretically possible as long as the rights and obligations remain balanced. In practice, fixed-term contracts are being offered for periods of between 1 and 3 years.