Jean Gabin did not receive an Oscar nomination for portraying Pepel Wasska in The Lower Depths.
The Lower Depths was later adapted by another great director Akira Kurosawa in 1957. The two versions differ greatly in terms of the general tone as well as the focus. Where Kurosawa made it a truly ensemble piece where all the various characters were more or less just as important, Renoir's version tightens the focus upon the thief living in the slum. The other characters are still there, but only have brief moments that are intertwined around the story of the thief Pepel played by Gabin. Again this character is played by the biggest star in the film, as Toshiro Mifune went on to play the character in Kurosawa's version. Gabin's depiction differs quite bit from Mifune, which can be seen from the earliest scenes. Mifune played it as though his thief was really just part of the crowd, that's not quite the case for Gabin's performance. Gabin gives the thief more overt of a style as a thief as he plays the part with a certain suaveness in the way he moves. He's not a low down dirty thief as Mifune played, rather Gabin plays him as a much more of the romanticized sort of thief. Gabin plays the part with a distinct smoothness in his physical manner as well as the way in which he speaks.
Gabin's approach works well with Renoir's approach for the material which is taking a bit of a lighter touch to the material. One of the aspects of this version is that the thief is made essentially to be the protagonist, which he's not in Kurosawa's, and it makes sense for him to be a made more likable do to that. Gabin is very charming here in portraying the thief with a very specific sort of cool that works also to portray the thief as someone who might live in the slum but never intends to be part of it. In addition with the possible murder plot involving the married couple and the thief is handled very differently here. Gabin very specifically shows that Pepel never even gives a second thought to being a murder, and instead plays his scenes with the wife a whole lot differently as well. Gabin does not show any true affection or desire to her but rather just Pepel lightly stringing her along in order for him to improve his circumstances by using her husband as a fence for stolen goods. This as well his thieving is technically amoral, but Gabin is able to get around this by suggesting not even the slightest violent urge in Pepel's heart.
With this different intent in mind Gabin makes Pepel a very endearing thief to watch apply his trade, especially when he goes to rob a baron, the baron does not mind because he has lost everything anyways. Instead they strike up a friendship in the night and Gabin makes this quite believable through just how much charisma he brings to the part. The scene the two share together is rather delightful as Gabin wins him over just as he seems to wins almost everyone over including the audience. Of course the murder plot is still hanging overhead in a way, even if Pepel wants nothing to do with it. This becomes all the more complicated when it becomes obvious to the wife that Pepel is far more interested in her husband's sister Natascha, despite her being quite critical of Pepel's choice of profession. Gabin is very good in the scenes between Pepel and Natascha as he so well reflects essentially the admiration in Pepel for Natashca because of her moral code. Gabin brings a genuine sweetness in these scenes and makes the romance feel natural.
Not everything goes to plan though as eventually a death does occur although in no way is it a murder even though Pepel is technically involved. Gabin is good in this scene though as he in no way expresses any other sort of character change in Pepel just rather plays in an authentic gut sort of reaction of the moment. Unlike the Kurosawa version this film is given much more of an happy ending, even though both do end with a suicide, and this version does not have the darkly funny punchline, but I'm getting off track. This version though does let the thief go so to speak as the thief is allowed to escape the suffering of the lower depths, and is given a far less rough treatment than Mifune's thief. This ending very well might not have worked as it technically can be seen as cheapening the tone of the story. Gabin manages to earn it though simply because he makes Pepel someone you do want to see escape his assumed fate. His performance works his way through any possible problems by charming his way through to the point that you simply want to see the thief walk away into the sunset with the woman he loves.