> I have never heard of this service
Maybe because it's French eheh. We don't have the same politics to go global!
For their pricing page, you buy Drops, which is like fuel for your car. They offer a better documentation here: http://doc.clever-cloud.com/pricing/ It will go from $600 (classical apps) to $2400 (huge apps) a year.
They designed their offer to be cheaper than AWS with same or better performances.