Where are you coming up with 20 different dialects of French? Are you talking about the various French-based creole languages, which are totally separate languages (e.g., someone from France has essentially no hope of understanding a native Hatian Creole speaker). If that's what you mean it's a bit silly to call them "dialects" instead of "separate languages" because Haitian Creole and French are as different as English and French.

Or are you talking about the various regional languages/dialects/"patois" in France? If so, sure, many could be called "dialects of French" but they aren't spoken at all outside of France so it isn't really relevant to Quebec.