Low cross-section tyres Approval criteria?

Hi, I have a great Golf 2 with 14 Brock rims. At the moment there are still the 195/45 tires, which the previous owner had mounted on it. Since the offer with a cross-sectional ratio of 40 is bigger, I would like to know what I have to look where to get no trouble with the dear state! Is this only according to the (registered) rims or is also interested in the car around it?