The film involved professional men (mainly middle-aged lawyers, bankers etc) joining an organisation that seemed to be something like a men's social club or perhaps the Rotarians or a Masonic Lodge - a sort of "do-gooding" / professional advancement organisation. Most of the scenes I recall (dimly) were set in office or club-lounge types of settings.
But it turns out that, unknown to him at first, circumstances lead to the main protagonist's life becoming forfeit,
I recall a scene in which he is made aware that this risk was entailed by membership - but I can recall nothing else, no title, none of the actors involved - just the details in one-sentence description.
I probably saw the film in the mid-late 1960s or early 1970s, as a rerun shown on TV in the UK - but it might have been made even in the late 1940s or the 1950s. I'm fairly sure it was post WWII.
I watch quite a lot of films but have never seen this rerun since.
It could well have been a "B" Movie (i.e. from the days when cinema programmes usually involved two films, with a cheaper B-movie shown before the main film.