Silver Bears (1977) on Netflix

Financial wizard "Doc" Fletcher (Michael Caine) is sent by crime boss Joe Fiore (Martin Balsam) to buy a bank in Switzerland in order to more easily launder their profits. When he arrives, Fletcher finds that the bank, acquired by his associate Prince di Siracusa (Louis Jourdan), consists of some shabby offices above a restaurant. To make up for this, the Prince suggests that Fletcher invests in a silver mine owned by Shireen and Agha Firdausi (Stéphane Audran and David Warner). This solves one problem, but the mine also attracts the attention of some of the most powerful people in the silver business. Fletcher must pull out all his wheeler-dealing skills in order to keep hold of everything he's worked for, in the process romancing a banker's discontented wife (Cybill Shepherd).