mct16:
if Herge was inspired then it would have been by the 1931 version starring Ricardo Cortez.
Or the
book (1930)? As someone who dislikes adaptations so much, I'm surprised that you leapt to the assumption that Hergé would have had to have seen a film version to be inspired... ;-)
The other problem is that the 1931 version of the film was not highly regarded, being thought too violent and "lewd" - a problem which meant that it couldn't even be shown in America after the Code was introduced, stopping it being re-released there in 1936; it would have to be established that it was even released in Belgium, if it was seen as a contentious film.
A possible contender might be
Satan Met a Lady, a 1936 rom-com remake of the same story, which starred Bette Davis. However it too was badly received, and Davis apparently described it as "junk".
I'm not certain that there is anything definitive to say whether or not Hergé was influenced by Hammett, but it's entirely posible as it has been a very popular and influential book since it first appeared.