Shoe sizes are not measured in the same units around the world. You can use this application to convert from the shoe size used in one country or region to the shoe size used in another country or region. Because of the many discrepancies between sizing systems and the differences between manufacturers, it is never a good idea to buy shoes based solely on these conversions. The best practice I can recommend, if the company allows this, is to place orders in terms of inches, millimeters, or centimeters.
The Mondopoint system is the same as measuring the foot (not the shoe) in Millimeters.