I actually did finish this several days ago. This was my second Maigret, and wasn't as good as The Yellow Dog, IMO.
I liked it, but I didn't love it. Maigret's behavior felt somewhat inexplicable to me throughout most of the book, and I felt like the solution to the mystery was fairly pedestrian. The ending of the book was surprising, though, and I'm still not sure what to make of it.
It was interesting - and I do plan to keep reading, but I hope that there are more like The Yellow Dog than there are like The Flemish House!