Repeating the ess after the apostrophe is not needed. What is Camille Saint-Saëns' birthday? will do.
Camille Pissarro was born on July 10, 1830.
Camille Paglia was born on April 2, 1947.
Camille Laurin was born on May 6, 1922.
Camille Coduri was born on October 8, 1966.
Camille Guérin was born on December 22, 1872.
Camille Claudel was born on December 8, 1864.
Camille Winbush was born on February 9, 1990.
Camille Desmoulins was born on March 2, 1760.
Camille Jordan was born on January 5, 1838.
Camille Henry was born on January 31, 1933.
Camille de Renesse was born on July 9, 1836.
Camille of Renesse-Breidbach was born on July 9, 1836.