At the Paris Motor Show, in October 1972, coachbuilder Chapron presented a Citroen SM in sedan configuration, called Opéra: with 4 doors, the tailgate was made of synthetic material. The wheelbase was extended by 19 cm compared to the standard SM and the length was 5.18 m or 28 cm more than the standard SM. The total production of the SM Opéra was of 8 units.