Complex sentence: His schooling was interrupted in 1899 when he was called up for miltary service and he joined the 41st Infantry regiment and in 1902 enrolled in the Ecole Nationale des Beaux-Arts in Paris studying sculpture.
Split into simpler sentences: His schooling was interrupted in 1899 when he was called up for miltary service and he joined the 41st Infantry regiment. In 1902, his military service over, he enrolled at the Ếcole Nationale des Beaux-Arts in Paris studying sculpture.