Article 91
1. Where the factors used to determine the taxable amount on importation are expressed in a currency other than that of the Member State in which assessment takes place, the exchange rate shall be determined in accordance with the Community provisions governing the calculation of the value for customs purposes. 2. Where the factors used to determine the taxable amount of a transaction other than the importation of goods are expressed in a currency other than that of the Member State in which assessment takes place, the exchange rate applicable shall be the latest selling rate recorded, at the time VAT becomes chargeable, on the most representative exchange market or markets of the Member State concerned, or a rate determined by reference to that or those markets, in accordance with the rules laid down by that Member State. However, for some of the transactions referred to in the first subparagraph or for certain categories of taxable persons, Member States may use the exchange rate determined in accordance with the Community provisions in force governing the calculation of the value for customs purposes.