Complex sentence: He began his career at Toulouse FC, but the bulk of his career was spent at RC Lens, with Lens he notably was champions of France in 1998 and the Coupe de la Ligue winner in 1999.
Split into simpler sentences: He began his career at Toulouse, but the bulk of his career was spent at Lens. With Lens he was part of the team who became champions of France in 1998 and the Coupe de la Ligue in 1999.