The comic actor will return as Georges Simenon's French detective on Christmas Eve.
Maigret In Montmartre will see the sleuth attempt to solve the murder of two women - a showgirl from a seedy Parisian club, and a countess.
Atkinson said: "Directors from film are seeing the value of television drama - that actually it doesn't have to be too obvious, it doesn't have to be overtly commercial. It just has to be good.
"And you can have scenes that go on for much longer than scenes would normally go on for, in movies even. Because you don't have to tell the whole story in an hour and a half.
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"You can tell it over nine hours. That's a huge freedom and a huge difference."
The Blackadder and Mr Bean actor, who has appeared in two previous Maigret episodes, said he was "braver" in interpreting the role the third time round.
He said: "I feel as though I started to relax with the character a bit more and have a bit more fun with Maigret and make him a little more human, rather than just someone who is rather stern, which is how I think he was in the first couple of films."
Maigret In Montmartre will air on ITV at 8.30pm on Christmas Eve.