Complex sentence: He started working in various nightclubs singing his favourite of the French chansons such as those of Édith Piaf, Yvette Guilbert and Marie Dubas, eventually getting a job at a specific club at which he worked continually for 40 years.
Split into simpler sentences: He started working in various nightclubs singing his favourites from the French chansons such as those of Édith Piaf, Yvette Guilbert and Marie Dubas. Eventually he succeeded in getting a job at a specific club wher he worked continually for 40 years.