Police from the finance squad have carried out a search of the headquarters of French President Nicolas Sarkozy's UMP party as part of an investigation into possible traffic of influence by Labour Minister Eric Woerth, party head Xavier Bertrand told the website lefigaro.fr Thursday.

Woerth is alleged to have obtained the Legion of Honour for Patrice de Maistre, who manages the fortune of L'Oreal heiress Liliane Bettencourt, in exchange for contributions to the party's campaign chest and a well-paying job for his wife.

Woerth himself pinned the decoration on Maistre in January 2008, three months after his wife, Florence, was given a job with Maistre's firm.

The search took place Wednesday and was the first time Sarkozy's party was targeted by the investigation, which was provoked by the discovery of secret recordings made in Bettencourt's house by her former butler.

According to the site parismatch.com, which first reported the search, the investigators were looking for traces of a letter written in March 2007, signed by Woerth and sent to Sarkozy, who was then interior minister and campaigning for the presidency.

In the letter, Woerth - who was then UMP treasurer and responsible for collecting campaign funds - urged that Maistre be awarded the Legion of Honour.

Party officials added that the police were also looking for any communications between Woerth and Maistre.

A high-ranking UMP official, Eric Cesari, told parismatch.com that police had given 24 hours advance notice of the search and that they had found nothing.

Woerth has repeatedly denied that the decoration was in exchange for services rendered to him or the party.

Woerth is also suspected of accepting an illegal contribution of 150,000 euros ($190,000) from Maistre for Sarkozy's presidential campaign in early 2007. He has also denied that allegation.