The ruling is a severe rebuff for the breakaway party, National Front - National Movement, launched by Mr Le Pen's former lieutenant, Bruno Megret in January. Mr Megret is already floundering in the opinion polls. The judgment could further undermine his credibility and end his chances of scoring the 5 per cent vote he needs to scoop seats and public cash in the European elections next month.
The court's decision was hailed as a deliverance and a great victory by Mr Le Pen's supporters. Several carloads of people - including his daughters, Marine and Yann, celebrated by driving up and down outside Mr Megret's modest headquarters in Paris beeping their car horns and screaming "On a gagne [We've won]!"
The split in the National Front (FN), the most consistently successful far-right party in Western Europe, has divided Mr Le Pen's own family. His eldest and most able daughter, Marie-Caroline, has defected to Mr Megret: hence, in part, the great joy of her siblings at the rebels' legal defeat.
Mr Le Pen, 71, is still in dire trouble, however. His own opinion poll ratings have scarcely benefited from Mr Megret's decline. A month or so ago, the polls were giving him around 7 per cent and Mr Megret 5 per cent. The latest surveys give Mr Megret's party only 3 per cent and Mr Le Pen 8 per cent. If confirmed in the election on 13 June, this would be the National Front's worst score in a French election since 1984.
Even the combined scores of the rivals in this ultra-right "primary" is well below the FN score in recent elections.
Another problem faces Mr Le Pen. In making its ruling, the tribunal said there was evidence that the party's founder-president had wilfully ignored calls from the grassroots for a national conference to solve the FN's problems. A judicial "administrator" has been appointed to investigate the claims of the Megret side that more than 20 per cent of the party's members had signed petitions calling for a congress.
If he decides that the rebels are right, the administrator will order Mr Le Pen to call a conference to which all who were FN members on 19 January could send delegates. This would included thousands of Megret supporters - though not Mr Megret himself. He was ejected the previous month.Reuse content