Originally from Menton, France, Lucien Gélas is well known for inventing and patenting a Guitar design which uses a double top, often called a Gélas Guitar, double-top Guitar or even a double-resonance-Guitar in 1905. 

This Guitar had two tops with a resonating space between them and The inner top is not parallel to the outer one. Also the strings run through the bridge (which is on the inner top) and are attached at the bottom, so the plucked part of the string before the bridge is at an angle to the part of the string after the bridge. Once he had this design he also used it on other chordophone including Ukuleles.

As well as his luthiery work, he was classical guitarist, composer and teacher. He won awards for his luthiery in 1907 and 1910 so clearly did make some of the instruments but given that he got a number of other luthiers to make some of his Guitars it is hard to say how much of a luthier he was in later life? He died in 1944.