Saw this on Talking Pictures channel (UK - old films and TV) who are running all 4 of the original Maigret series (BBC, early 60s). By sheer coincidence, another UK channel is showing the Gambon version (2 series, 6 episodes in each) and this exact story was on the night before!
As reviewer Sir-Obolong-Fizzobolongs says, (accurately for once!), these versions are well matched, with the Gambon one giving Maigret a little more time to exert psychological pressure on the suspect, and the 2 awful women in his life, and he's helped by the roles of the 2 women being played slightly better - though that issue could have been due to the director? But the older version, that has a greater pace (only an hour runtime) and the outside filming does indeed have a greater urgency, and threat.
A feature of the story is the suspect's suit, damaged, and given to a tramp. The modern Atkinson version had lots of time to fill, and padded things out with much detail about looking for the tramp, then extended forensic analysis of the suit. Gambon's story pretty much ignored the tramp & suit, but this one had poor Torrence detailed to "scour Paris for the tramp". Luckily he found tramp & suit in record time so it could feature in building a case against the suspect!
Though the dialogue is some places is pretty much identical, this one has Maigret being even more brutal in his analysis of, and speech to, the suspect, likening him to "a pet dog with 2 owners" (etc).
I'd have given this a 10, but for a slight doubt about the 2 women in the suspect's life (even though one of them did go into the initial Dr Who soon after, and is famous with fans of that show).