I am not quite sure but I think that the French Academy (Académie française) is the French institution that is the canonical guardian of the French language. 
(https://french.stackexchange.com/questions/18405/what-organization-is-the-official-guardian-of-the-french-language-in-france-and)

I do know also that there was a French Grammar supervised by the French Academy 
([LA GRAMMAIRE DE L’ACADÉMIE: PAR M. ABEL HERMANT, DÉLÉGUÉ DE L’ACADÉMIE FRANÇAISE, 1930][1])

This grammar was considered in the past as an official French Grammar? What was the reactions to this work? Is there something relevant but more recent one?

Grevisse's Le Bon usage is considered as the Definite French Grammar?


  [1]: http://www.academie-francaise.fr/la-grammaire-de-lacademie-francaise