Fanfan, a lazy young man from Paris escapes from a forced marriage to the daughter of farmer and joins the army after Adeline promised him a glorious career in the French Army. After singing the contract, he finds out that Adeline is the daughter of his sergant. In spite of this he tries to make the "promised faith" of him true, but he is caught when he tries to intorduce himself to Louis XV's daughter Henriette, who he shall marry due to his promised faith. He is sentenced to death, but Adeline convinces Louis XV that he shall be free. But Louis XV hasn't done this for free. So he tries to kidnapp Adeline. Fanfan chases the kidnappers, but he has no sucess in this, but he captures the military enemies supreme command. For this he receives the thanks of Louis XV. He promotes him and he's allowed to marry one of his daughters, Adeline, who has been adopted by Louis XV.
Source : IMDb