Facile à dire! 

This thread at Wordreference French forum gives links to dictionaries, sites that can help with verb conjugations, and sites for general help with French grammar. 

A French thesaurus. 

Lexilogos has links to numerous French (monolingual) dictionaries, including dictionaries of Old French and French language from the 16th-20th centuries.

Vis-à-vis Online Learning Center:

Embassy of France in Washington:


Le Devoir:

Le Monde: