He kinda nicknamed himself "le chanteur énervant" (the annoying singer) probably because he has no problems voicing strong opinions in his tunes. He's kind of a child of the May 1968 strikes and I guess he had a whole lot to say about French politics when he got started. He actually wanted to be a comedian/actor (that kinda explains why he was in a few movies, in particular, "Germinal" with Depardieu) but ended up being mostly a singer/songwriter. His tonal range is about 2 notes (joke) and his voice can a tiny bit grating at times. Definitely, not everybody's cup of coffee. He uses a lot of old-school slang in his songs and that makes his lyrics particularly fun, especially the early stuff.
That's where it all stated for him: "Laisse Béton".
Now, the title of this song is in what is called "verlan", a form of slang where you invert the syllables. So, "Laisse Béton" is really "laisse tomber", which means "let it go".
The 80s with "Mon Beauf".
"Beauf" is slang for "beau-frère", "brother-in-law". In the 80s, he wrote a lot of light and funny tunes like this one.
The 90s with "Morgane de Toi".
"Morgane de Toi" is (old) slang for "amoureux de toi", "in love with you".