Antique French advertising trade card for Chocolat Guérin-Boutron, issued by Maison Guérin-Boutron, Paris, from the celebrity portrait series. The printed series/card detail is 2e Livre d’Or / Célébrités Contemporaines No. 501 — Princess Olga of Russia; the front caption reads “Princesse Olga, de Russie” (Princess Olga of Russia). The front shows Princess Olga as a young girl in a pale dress, framed by the decorative green Chocolat Guérin-Boutron border with floral corner ornament. The portrait format and numbered caption make it part of the firm’s Célébrités Contemporaines / Livre d’Or celebrity issue. The reverse is headed with 2e Livre d’Or: Princesse Olga de Russie, née en 1895, fille aînée du tzar Nicolas II et de l’impératrice Alexandra. It also carries Guérin-Boutron advertising for Chocolat de Qualité Supérieure (superior quality chocolate), the Paris retail addresses, the Rue du Maroc chocolate factory, exhibition-medal wording, and the red recommendation for vanilla chocolate sold at 2½ francs per kilo. A collectable example for buyers interested in French chocolate advertising, Guérin-Boutron ephemera, celebrity portrait cards, theatrical and royal subjects, and early colour-printed trade cards. Condition shows age toning, light soiling, softened corners, edge wear, small marks and general handling wear visible in the scans. The portrait and printed advertising remain generally clear and legible. Condition as described.