Lun Cossier, known as Walles, is a painter of French nationality born on January 2, 1946 in Poland to French parents. He received a Master's degree from Academie des Beaux Arts in Krakow (Cracow). The artist spent much of his childhood in Poland surrounded by Byzantine influences in the churches and monuments. His paintings therefore have a mosaic-like quality to the surfaces, achieved by using small palette knives to form tiny squares and triangles, as well as a jewel-toned palette.

Walles lives and works in the Paris area where he exhibits regularly. His pseudonym derives from part of his Polish name.