Estimates of between 20-80k Moors but more likely 30k were there versus around 20k of Frankish/Burgundian forces. Also Charles won without cavalry which was very impressive regardless of any battle but especially against the Umayyad who had good heavy cavalry that had already decimated other Frankish forces a decade earlier. He basically used phalanx type of well trained heavy infantry to stop the cavalry charges while also being uphil and having the forest as cover. He outmaneuvered and outsmarted Rahman who was a good commander.
The Moors got greedy as they heard that the Franks were attacking their base camp and stealing their loot so they began to withdraw to save their booty and in the ensuing chaos Rahman was killed and thus ended the battle.