I’m not sure where this cocktail got its name. But if you have more than one, you might find it hard to keep your chin up.
Cynar is an Italian liqueur made from artichokes and is quite a force to be reckoned with due to its intense bitterness, balanced here by the cucumber, gin, vermouth, and pinch of salt. It’s not hard to find in the States in well-stocked liquor stores. In France, you may have luck finding it in an Italian epicerie. If you can’t get it, you could try another Italian
amaro,
Fernet-Branca, or even Jagermeister, in its place. If so, traditionalism may require you to change the name. But that’s part of the fun of inventing your own variations.