This is a lovely example of a late 19th-century French chromolithographed pop-up (or "stand-up") advertising card, produced as a promotional giveaway for Félix Potin, the famous Parisian grocery and épicerie fine chain.
The piece is a paper theater in miniature — a single sheet of heavy card that folds flat for mailing or storage, then opens into a three-dimensional street scene. When erected, a lithographed backdrop rises vertically showing the Palais Garnier seen across the Place de l'Opéra.
The signature "Ch. Arnal" visible on the pavement is Charles Arnal, a prolific Parisian commercial illustrator of the Belle Époque who did a good deal of chromo work for grocers, chocolatiers, and department stores.