I've really enjoyed this series. There is an element of the mystical, and a small element of horror, but it remains a series about ordinary crime at heart, with fairly ordinary people.
One of the things that I've enjoyed is that it has avoided escalating in the way that many urban fantasies do. The series is also quite good about revealing more about the characters as it progresses. It feels well-crafted and well-thought out.
Although there were some things that happened that struck me as being very unrealistic (in terms of how people might react in a situation), it wasn't enough to ruin my enjoyment of the series. I'm really looking forward to the next season.
I should also add that, while it's in French, the English dubbing is a lot better than many other shows that I've watched.