A letter by former US President Bill Clinton is set to play a key part in a court case brought by French underwear maker Hom against tights and hosiery firm Dim.

Hom is seeking compensation of up to 800,000 euros from the Sara Lee unit amid claims Dim plagiarised its successful 1997 men's brief with a horizontal, instead of vertical, opening.

The case will be heard in Marseilles and will see Hom's lawyers produce a letter dated March 1997 from Clinton in which he says he was satisfied by "this good French product".