Gaillard is one of the great Parisian chaudronniers. Founded in 1795, the workshop at 81 Faubourg Saint-Denis became famous for the thickest, heaviest professional copper. In 1903 Jules and Émile Gaillard took over as J. & E. Gaillard, and after they parted in 1919 Jules continued alone - those "Jules Gaillard Paris" stamps from 1920-1930s are considered the last golden period of French copper before WWII.

Like Dehillerin, Gaillard didn't just sell pots - they supplied the grand hotels and Rothschild kitchens of Paris. You can still feel it in the weight: 3-4mm hammered copper, cast iron handles, hand-finished

Here you can compare your own Gaillard stamp with the ones I've collected so far.