Before which authority: The court of the first instance
According to which procedure (state the applicable rules): An ordinary judicial procedure
In the course of contentious proceedings it is possible to introduce evidence that proves the contrary of the authentic instrument. Proof to the contrary requires sufficient evidence to discharge the full burden of proof. It is not enough just to put the evidentiary value of the authentic instrument in doubt.
Within what timeframe: Authenticity may be challenged at any time, at least until the authenticity of the document is established by an irrevocable decision.
