Review of The Adultress

What was the point? First saw this a few years ago and enjoyed it.having recently read the novel I decided to rewatch it .and was seriously disappointed vellone and sylvie are terrific but miss signoret is badly miscast she is just too worldly for the role.also why the update.and the major plot changes.a planed murder becomes a spur of the moment one.and I take it the invention of a blackmailer is ment to be a physical representation of their guilt.and why change the ending.what is almost a suicide pact.becomes a just a twist in the tail ending.as good as mr carne is.he should have had more faith in the original.