I can't say I am much aware of what is going on in French cinema, but from time to time, for a change, I make time to watch French creations on the topics I like most. So, after e.g. Braquo and Engrenages, I was redirected to En Immersion.
Black-and-white approach is often good, but in the series where practically nobody has any delight in their life, only various problems, it provides too burdensome background for a work where thrill and crime should dominate over personal and health issues. Thus, the pace slowed down, yet there were attempts to link different fates into related loop - characteristic to Nordic noir - but they resulted in both unnecessary over-sophistication and scenes, not speaking of dubious shifts and settlements. It seemed that Episodes 1 an 2 had all the time to "waste", but Episode 3 summed it all up in a certain hurry. Good that the ending scenes were not plain, though.
The cast was quite unknown to me, only Olivier Chantreau (as Guillaume Leanour) was familiar, but his character was a bit trivial to play. The ones depicting Serrero family were just okay, nothing special.
All in all, En Immersion does not measure up to e.g. Virage Nord also shown on Arte, but it is no flop, by all means. Just be prepared to follow more mysticism and mental issues and less criminal stuff.