From a recent exhibition in Paris, summarized at this web site comes this account of the General's role in the liberation of France:

General Charles de Gaulle was one of the pioneers of modern armored warfare as practiced in the Second World War. His writings, although initially ignored, eventually led to his assuming command of the newly-created French 4th Mechanized Division in May, 1940, just as the German invasion began. The counterattack he made did not save his country, but was one of the few bright moments in the national disaster. He was appointed Under-Secretary for War and was in London, meeting with the British, when France fell. The government of which de Gaulle was a member refused to surrender, but was replaced by one led by Marshal Petain, who did. De Gaulle refused to accept the new government, and made a radio broadcast to the French people, saying - "France has lost a battle, she has not lost the war." - and urging them to continue the fight against Germany, from the French colonies, if not from France.

Based upon his position as a member of the last legitimate French government, the British recognized de Gaulle as leader of the "Free French" assisting his plan for resistance to the pro-German "Vichy" government in France. The British also recognized governments-in-exile for other countries occupied overrun by the Germans, e.g., the Free Polish, Free Czechs, Free Norwegians, etc. These were of value for propaganda purposes, as sources of spies and saboteurs to be sent back to the occupied countries and for helping thousands of young men to escape from Europe and form regular military units to fight against the Germans.

Unfortunately for de Gaulle, the British, fearing that the French fleet at Mers-el-Kebir, (in North Africa) was about to surrender to the Nazis, tried to force it to defect to him. When the French refused, the British attacked, sinking the ships and de Gaulle's hope of widespread support in France.

Another problem for de Gaulle was that the United States had already recognized the "Vichy" government and Roosevelt felt he could not legally recognize the Free French as well. When America entered the war, this led to a confusing "Two France Policy", with the British and Free French being at war with the Vichy government while the Americans were not. Even after U.S. forces invaded French North Africa in November, 1942, FDR wanted to replace de Gaulle with his rival, Gen. Giraud, which led to endless friction in the Allied high command.

However, by 1942, in spite of Mers-el-Kebir, the brutality of life under the Nazis had convinced most Frenchmen that de Gaulle had been right to reject the surrender. Free French forces grew stronger, and resistance to Vichy rule increased. These forces played a vital role in the liberation of France and the final defeat of Nazi Germany.

Having left France after the Marshal Philippe Pétain concluded an armistice with Germany, de Gaulle - a French army officer at the time - made his famous appeal of 18 June 1940 from London for a French continuation of the war against Germany. This was the beginning of the Forces of Free France - Forces Françaises Libres.

De Gaulle entered Paris on 25 August 1944, and that evening gave one of his most memorable (and improvised) speechs (Français / English) from the Hôtel de Ville. The next day (26 August 1944), he paraded down the Champs Elysées in triumph together with the 2nd French Armored Division of Général Leclerc to Notre Dame.