How was charles de gaulle instrumental in defeating the germans in france? i know he really wasn't but my french teacher is not going to accept that answer

Hi !!

Le général Charles de Gaulle refused the armistice between "Le gouvernement de Vichy"  held by Maréchal Pétain who was a collabo (german collaborator). He approved German ideas, he rejected equality between men (antisemitic), changed our motto "Liberté, égalité, fraternité" into "Travail, famille, patrie" (work, family, fatherland). His government was an authoritarian regime. The armistice Pétain signed on June 22, 1940 was giving Germany over the North and West of France, including Paris and the atlantic coast... There were many pro-german conditions
Général de Gaulle refused this armistice with Nazi germany. He wanted "Une France Libre"(Free France).
 He launched "L'appel du18 juin" (the appeal of June 18) from London by the BBC.He exhorted the French population to resist and join "Les Forces Françaises Libres" (The Free French Forces). De Gaulle went to London when he realized Pétain was going to sign an armistice with Hitler. He wanted to fight till Germany was defeated.
He was sentenced to death by Pétain .

So, he acted from London to free France completly from german Nazi.
He was the chief of the "Résistants" who helped to free France helped by the Americans, the British, the Canadians

this is a short resumé...hope it will help !!