In 732 at the battle of Tours,
Charles Martel defeated the Moors.
A small quibble, but important.
There was no France yet, in 772. There were only Gauls, Germans and the remnants of Rome in Western Europe at the time, not counting the islands and Scandanavia.
Martel led the resistance, and he was king of the Franks. The Franks were just another german tribe then.
The Islamic Moors conquered most of Spain in 711 A.D. after the descendents of the Visigothic warriors that had conquered Roman Hispania in 415 A.D. had become a decadent and lazy ruling class with the passage of time.
The Christians made a stand in the mountain strongholds of Galicia and Asturias and defeated the Islamic Moors in 718 A.D. at Alcama thus turning the tide of Islamic conquest.
Thus began the Reconquista of Spain that lasted until Granada, the last Moorish kingdom in the Iberian Peninsula, was conquered in 1492.
The Reconquista was the earliest, the longest and the only completely succesful European Crusade in Christendom.
The Surrender of Moorish Granada, 1492
The only flaw in your story is that the French did not stop the spread of Islam in Europe. Charles "the Hammer" Martel was born in 688-690 in Heristal, Liege, a German city located in modern day Belgium. It took another two generations to drive all the Arab garrisons out of what is now France and across the Pyrenees, Charles Martel's halt of the invasion of French soil turned the tide of Islamic advance, and the unification of the Frankish kingdom under Charles Martel, his son Pepin the Short, and his grandson Charlemagne prevented the Umayyad kingdom from expanding over the Pyrenees.
The Crusades were not a case of Christian aggression. The proximate cause was the presence of the Seljuk Turks in the Middle East ~ an area which was NOT their home country.