Hello!
I was able to find the registres matricules of Henri Célestin Grasset and then his birth record. He was born 16 March 1867 in Marseillan, Béziers, Hérault, Languedoc-Roussillon to Joseph Simon GRASSET and Jeanne PRADEL. I am attaching his birth record and registres matricules.
Henri Célestin Grasset married Virginie Marie Françoise NICOULEAU on 25 October 1889 in Marseillan. They had a child named Gabrielle Françoise Grasset who was born 8 July 1891 in Marseillan. I cannot find anything else about Gabrielle Françoise. Virginie Marie Françoise Nicouleau died on 11 April 1894 in Marseillan.
I could not find the marriage record of Henri Célestin Grasset and Marguerite Lucy Marie BOSCH. I could not find the birth record of Antoine Rahpaël Grasset. I did find the birth and death record of another child born to Henri Célestin Grasset and Marguerite Lucy Marie Bosch: André Célestin Grasset was born on 27 January 1902 in Marseillan and died 26 March 1902 in Marseillan.
Marguerite Lucy Marie BOSCH was born Margarita Lucia Maria Bosch in 1872 in Vilamaniscle, Gerona, Spain to Rafael BOSCH and Rosa MASO. She was baptized on 14 July 1872 in San Gil, Vilamaniscle. Her father, Rafael Bosch, was born in 1842 to José BOSCH and Teresa PALAU. Her mother, Rosa Maso, was born in 1845 to Andres MASO and Maria SIMON.
I hope this helps. I am sorry I could not respond in French.
Cheers,
Soosi