It doesn't surprise me that as I write this, there are no reviews of Mongeville. Playing on MHz right now, it's a difficult series to sum up. First, each episode is around an hour and a half, which makes each one a kind of mini-movie. Second, the first three episodes are quite different than any that come afterward. Initially, the main characters are Axelle Ferrano, a female lieutenant on the Bordeaux police force, and Antoine Mongeville, a retired judge. She is a serious, somewhat moody character, who exudes a subtle sex appeal. He is an aging, investigative judge who is still sharp, and still wants to keep his nose in the game. They bond over the fact that they have both suffered great losses in their lives, and form a very effective investigative team, which sometimes seems father-daughterish in nature, and sometimes even has a hint of romance about it. For three episodes it is a somber and quite engaging series.
However, after those three episodes, the actress, who plays Ferrano (Marie Moute) left for greener pastures, even though her story was completely unresolved.
So in the second season Ferrano/Moute was replaced by a new character, a female detective, who could be called "perky, bubbly, fresh, humorous," you get the idea. All of a sudden what I had thought was a serious detective drama became something that could be labeled "breezy, charming, light." "Prime Suspect" had become "Midsomer Murders."
I like my female detectives hardcore, like Laure Berthaud in Spiral. I don't want to see female detectives arriving at the crime scene tripping over their high heels and carrying big handbags. To make matters worse, Mongeville didn't even pay the original character the respect of offering a good explanation for why she left. At any rate, if you like light and charming, you might thoroughly enjoy Mongeville. For me, however, after episode three it lacked the gravitas needed to keep my attention.