The ruling by judge Jean-Jacques Gomez Monday to compel Yahoo! to prevent French internet users accessing part of its US site –- the part which offers Nazi memorabilia available for auction -– is far from complete. The complaint targeted two companies, Yahoo! France and Yahoo.com. But even if the French affiliate is forced to comply, what could persuade the US holding company to follow suit and set up filters on its own systems? "For the French decision to be applicable in the US, both countries have to have signed an international convention for mutual recognition of legal decisions," explains Gerard Haas, attorney of the bar of Paris. "Such an agreement does not yet exist between France and the United States. Furthermore, this decision is not in harmony with American law, which promotes freedom of expression. An American judge needs to declare the French decision applicable on the American territory –- this procedure is referred to as 'exequatur'." According to a member of the American legal firm Skadden Arps, this exequatur procedure may be triggered by simply addressing an American judge and getting him to acknowledge the French decision as actionable. For French minister of justice Marylise Lebranchu who spoke at a conference organised by Licra (League against Racism and Anti-Semitism) on 16 December, "the International character of the system and settling of various protagonists abroad is not an obstacle for French justice. As soon as the litigious message is accessible on French territory, French penal law is applied and a French penal judge is competent to know the offence." But she also underlined that "obstacles, notably in getting national legal decisions approved and applied abroad, can only be overcome thanks to international cooperation". Even outside the US, filtering will only be a partial solution given that each Internet user does not carry his or her national flag with his or her IP address. Experts estimate a 70 percent efficiency for .fr filtering. For the others, ruled Gomez, if the filtering is inefficient Yahoo! will simply have to implement what the experts proposed: "a voluntary declaration of nationality". Yahoo!, which seems to have decided that Nazis aren't dangerous but paedophiles are. But Yahoo! seems to be arguing on principle. At least David Coursey hopes it isn't because the company is too lazy or stupid to fix its software to make the French happy. Amazon and eBay have taken reasonable steps to comply with French law. Like the wise man said, "It's only software." Go to AnchorDesk UK for the news comment. Have your say instantly, and see what others have said. Click on the TalkBack button and go to the ZDNet News forum. Let the editors know what you think in the Mailroom. And read what others have said.