Taking a contract in a Schengen state

I'm a Canadian with residence in France, but not a citizen of France. I'm working for a French company, and I want to compete on contract positions in other Schengen states.

Does someone know whether there is one rule or does each country have its own rule?

For example, I talked to the German consulate and they said I can stay and work in Germany for up to three months before requiring a work permit.

Does this apply to the other Schengen states?

Every time I look at the different government sites (i.e. Belgium), I seem to fall through the cracks. It just doesn't mention my situation.