Sewers Of Gold 1979

AKA 'Dirty Money' & 'The Great Riviera Bank Robbery'.
About 25 minutes in: Some crooks are holed up in a villa, one evening the police call. A crook answers the door in his dressing gown. A woman, (possibly Laraine Humphreys), appears behind him to make it look like the two of them are on a romantic getaway. She is wearing an off-white possibly pale pink fullslip with generous lace at the bust, it looked soft and silky, narrow ribbon straps, didn't see the hem. Lasted about 15 seconds