It is difficult to know where to begin with this one. Much of the weakness was neatly skewered in The Guardian tinyurl.com/gttg2zv. It is better left to proper experts to judge whether we we watching Mr Bean does Maigret or Johnny English does Maigret. The tired but contented-with-a-job-well-done expression in the final moments was a great treat, though.
It was nice to know that the French police operated a looks only recruitment policy for its female section at the time. When Atkinson decreed that he wanted the ones he'd selected as bait for a serial killer to be "all trained in self-defence", it was unclear whether he meant ones already trained or that his selections had to be trained that afternoon. Judging by the performance of the one who did succeed as bait, it was the latter. And trained by the man who cleaned out the ashtrays.
The answer to the one piece of - quite arbitrary coin-toss - suspense will remain confidential. Otherwise future viewers would have the excuse that this blog had spoiled the programme for them. After the effort of producers, director and cast there was not a lot to do in this direction.
Exercising the prerogative of a grumpy old man it is enough to point out the many inauthenticities. Once we'd got past the correct Citroen Tractions Avant (balm to Rupert Davies fans and tractionists such as the author) they came almost without interruption. Budapest only looked like Paris to some people who had never been to Paris or Budapest. Atkinson and his acolytes were constantly telling each other to "take him (or her) to the Quai des Orfevres", just in case we'd forgotten this was happening in a French city. No French office ever kept (or keeps) beer for its employees. Le Monde did not carry photographs on the front page until the 1990s or later. It was and is written in correct French.