“Je ne suis pas d’accord avec ce que vous dites, mais je me battrai jusqu’à la mort pour que vous ayez le droit de le dire.” (“I do not agree with what you say, but I will defend to death your right to say it.”) – Voltaire

Just as this famous French philosopher promised, the French have the right to speak their minds and boy do they do just that.  In fact, there are many ways to disagree in French beginning with “Je ne suis pas d’accord” as Voltaire said all the way to “tu n’as pas raison / vous n’avez pas raison” and “tu te trompes / vous vous trompez”.

If you want however to express that you agree with something someone has just said, you could say “Moi aussi” if agreeing with a positive statement or “moi non plus” if agreeing with a negative statement.  You say “pas moi” to disagree with a positive statement and “moi si” if disagreeing with a negative statement.  Sounds complicated?  I’ll give you some examples:

J’aime le chocolat.

You like chocolate too: Moi aussi.

You don’t like chocolate: Pas moi.

Je n’aime pas le chocolat.

You don’t like chocolate either: Moi non plus.

You do like chocolate: Moi si.