Using "si" instead of "oui" to disagree with a negative question or statement in French

In most cases, we use oui (yes) and non (no) in French the same way as in English.

However, if someone asks you a negative question or makes a negative statement and you want to disagree with it (i.e. answer in the positive) then use si instead of oui.

Learn when to use "Si" or "Oui" in French 

Summary:

- Use Oui to answer "yes" to positive questions/statements

- Use Si to answer "yes" to negative questions/statements 

Note that non is always the same whether you are agreeing or disagreeing: