Copé reacted furiously to allegations in the magazine Le Point that he allowed a company run by personal friends to overcharge the Sarkozy campaign, accusing the weekly's editor, Franz-Olivier Giesbert, of waging a long hate campaign against him.
"Franz-Olivier Giesbert's hostility towards Nicolas Sarkozy and myself is well known," he declared in a circular to party members on Thursday. "It has been openly expressed for several months through hate-filled editorials and pathetic televisual outbursts."
He went on to accuse the magazine of "dishonest accusations" and "disgusting insinuations" and declared his intention to sue.
Giesbert replied that "conspiracy theories are an illness".
Le Point claims the Bygmalion company, run by Bastien Millot, a former chief of staff of Copé in his capacity of mayor of the town of Meaux, and Guy Alvès, who was Copé's chief of staff when he was budget minister, made at least eight million euros out of Sarkozy's election campaign and that much of the profit came from overcharging.
Bygmalion's subsidiary Events et Cie organised Sarkozy's election rallies and handed in bills that rival campaign organisers judge "disproportionate", according to Le Monde newspaper, for example 26,359 euros for lighting at a meeting in Paris and 3,048 euros for an internet connection in Saint-Brice-sous-Forêt, north of the capital.
Copé's defenders, including campaign treasurer Philippe Briand, claim that it would have made no sense for Copé to swindle a party whose leader he intended to become after the election.
Le Point also judges the source of Bygmalion's finds "mysterious", claiming that a "phantom investor", Emmanuel Limido, runs an investment fund popular with investors from Qatar, the Gulf state that bought heavily into France during Sarkozy's period in office and continues to have considerable interests here.
The magazine raises doubts about the legitimacy of the sale of a plush hotel and conference centre in Paris to Qataris while Copé was budget minister, implyingthat Limido was involved in the latter sale.
Former prime minister François Fillon, who fought Copé for the UMP leadership in a contest that caused bitter rifts in the party, dismissing them as not worthy of attention, although one of his supporters, Lionel Tardy, tweeted "Everbody knew about @jf_cope. That's why I didn't take part in the Sarkothon".