I applied in-person. The process took 3 months. I interviewed at Celsius Online (Paris) in Dec 2013
Interview
At first, I had to pass a 1hour test. It was a mix betweeen JavaScript and PHP.
After that, I had to discuss with the CEO and CTO about the test, about my experiences, my games.
It was really funny and friendly, I had no stress when I discussed with them because they made everything nice.