Complex sentence: Trenet wrote the lyrics of "La Mer" on a train in 1943 while travelling along the French Mediterranean coast, returning from Paris to Narbonne, supposedly in ten minutes, on toilet paper supplied by SNCF.
Split into simpler sentences: Trenet wrote the lyrics of "La Mer" on a train in 1943 while travelling along the French Mediterranean coast, returning from Paris to Narbonne. He supposedly wrote the song in ten minutes, on toilet paper supplied by SNCF.