C’est si bon was composed by Henri Betti and means It’s so good. Yes, this song is sooo good to play and improvise over.
Actually this song is a french pop song but we often play this song in gypsy jazz.
C’est si bon transcription
Melody is easy to play and make you feel good to play.
Unusual in gypsy jazz, there are so many chords but it’s not too hard to remember.
I use G6 where it’s written G. You can also use Gmaj7, G69, or just G maj.
Solo
Probably no need to explain the melody. It’s simple and easy, right?
Just one thing I would tell is that I start the melody lines from 7th fret(D)→6(C#)→5(C) on 3rd string but you can practice to play from many positions. you can start 5th fret on 5th string, or 10th fret on 6th string .
It’s very useful to be able to play from many positions when you improvise over . It’s not easy but you will get used to it.
If you are not good at improvising, take a look at gypsy jazz arpeggio lesson. Most of gypsy players use arpeggios to improvise like Django.
You can also take a look at Popular Gypsy Jazz Method Books for self-taught guitarists. I also used this kind of books to learn.