I'm not sure. I can't think of an example of a name that combines English and French elements. Some French surnames from given names are Germanic in origin, the Franks were a Germanic tribe who adopted the Latin based French language, but often used the same Germanic elements to make up names. The French Renard is the same as the German Reinhardt, and the English adopted the French version making it Raynard and Rayner. There are lots of examples like that. I think maybe Leonard is a hybrid, French leon, "lion", and Germanic hard.