(Adds detail of other investigations)
By Douglas Bakshian and David Milliken
LUXEMBOURG/BRUSSELS, Sept 18 (Reuters) - The European Union's top court upheld a 90 million-euro ($101.6 million) fine against Volkswagen on Thursday, punishing the continent's biggest car manufacturer for unfair sales practices.
The European Court of Justice dismissed Volkswagen's appeal of a 1998 fine and ordered each side to pay costs.
The European Commission had originally fined Volkswagen 102 million euros for restricting Italian distributors from selling its cars to German and Austrian customers during the mid-1990s.
A Volkswagen spokesman said the ruling would not impact its profits because it had already made provisions in its accounts.
"The conditions for selling cars have changed considerably thanks to the introduction of the euro and the block exemption," he said in reference to new EU Commission rules on car sales.
The fine was a record at the time for a single firm.
The EU's Court of First Instance reduced the fine to 90 million euros in 2000. Since then, penalties in other cases have dwarfed it. In 2001, a group of vitamin manufacturers were fined 855 million euros.
The Court of Justice said that from 1993 to 1996 Volkswagen had made life tough for Germans and Austrians who wanted to cross the Alps to take advantage of lower Italian car prices.
"To restrict these parallel imports from Italy, Volkswagen and others limited the supply of Italian dealers and introduced a bonus system that Italian dealers with sales to non-Italian customers were kept out of," the court said after the ruling.
The EU's executive, in charge of policing internal market issues, had earlier ruled this breached EU rules designed to ensure free trade of goods and services between member states.
Other car manufacturers have fallen foul of the same rules. The Commission fined General Motors's Dutch unit Opel 43 million euros in 2000 and demanded that Daimler-Chrysler pay 72 million euros the following year.
The Commission is now investigating France's Renault and Peugeot for similar breaches.
The Commission welcomed the ruling, saying it gave EU consumers the freedom to buy cars where they wish.
"Manufacturers may not impose supply quotas or bonus systems on dealers in one member state that discourage dealers from selling to residents of other member states," it said.
New Commission rules loosening the grip of car makers on dealers began to take effect nearly a year ago. Many of the rules become final on October 1 and some take effect next year. (Additional reporting by Jan Schwartz in Hamburg)