The French had some of the most incredible leaders of the century, Napoleon for a start, Davout who equaled if not exceeded Napoleon's own military genius. Ney, Lannes, Soult, Massena, Suchet, Saint-Cyr, Berthier, Murat and many excellent generals.
Numbers were definitely NOT the reason France was so successful in the Napoleonic wars. As stated earlier it was they who revolutionized how war was fought.