PARIS (Reuters) - A French public prosecutor on Thursday opened an investigation into the financial dealings of the head of Emmanuel Macron’s successful presidential campaign, throwing a new spotlight on sleaze in a fraught election year.

The preliminary probe comes 10 days before a parliamentary vote where Macron hopes his new political party Republic On The Move (LREM) will win control of the National Assembly and consolidate his grip on power after his own election on May 7.

Opinion polls so far show he is likely to achieve that aim, and that the affair surrounding Richard Ferrand, now a minister in the Macron government, is not impacting voting intentions.

Two of Macron’s main opponents were hamstrung by corruption allegations during the bitter battle for the presidency and his government has put political probity front and centre in its first two weeks in power. Thursday also saw justice minister Francois Bayrou outline plans for new anti-graft legislation.

A voter survey earlier this week showed most feel Ferrand should step down.

“Is there a risk? (for the parliamentary election result) The answer is yes,” Jean-Paul Delevoye, the man in charge of choosing Macron’s party’s candidates for the parliamentary election, acknowledged to reporters at the European American Press club. But he added he was nevertheless confident of having a solid majority in parliament.

Failure to secure a majority in the June 11 and 18 election could put Macron’s centrist, pro-business reform agenda at risk by forcing him into an uncomfortable alliance, most likely with mainstream conservative party The Republicans, which is still smarting from defeat in the presidential poll.

In France, the opening of a preliminary inquiry does not imply guilt. Prosecutors decide after such preliminary checks whether there are grounds for a full-scale probe or not.

French Territorial Cohesion Minister Richard Ferrand arrives at the Elysee Palace before a weekly cabinet meeting in Paris, France, May 31, 2017. REUTERS/Charles Platiau

NO REASON TO QUIT

Prime Minister Edouard Philippe told reporters the inquiry changed nothing. “As long as he is not placed under formal investigation there is no reason to ask Mr Ferrand to leave the government,” he said.

The public prosecutor in the western city of Brest said he had decided to open the inquiry after a string of media reports about the business and financial dealings of Ferrand, minister for territorial planning and a former Socialist who became one of his key early backers.

Media reports about Ferrand focus on his management of a medical insurance group in Brittany six years ago, notably a decision to rent office space from his partner.

Another issue is his hiring of his son for four months as an assistant paid from parliamentary funds.

Ferrand has denied wrongdoing, and while hiring family as parliamentary assistants is banned in some countries, it is not illegal in France.

Failed conservative presidential candidate Francois Fillon’s campaign was derailed by sleaze allegations and he is now under formal investigation, not because he paid members of his family from public funds, but because of allegations that his wife in particular did not do much actual work for the money.

Declining to speak about the Ferrand case, new justice minister Bayrou unveiled ideas for a new draft law on ethics in public life to be presented to cabinet in June.

The proposed new legislation to clean up political practices would ban hiring of family by members of parliament.

“For years and recent months have been particularly fertile on this subject,” Bayrou told a news conference. “We have seen habits that have destroyed people’s confidence in their elected officials.”

Far-right leader Marine Le Pen, another failed presidential candidate, is also under investigation with regard to the hiring of party activists as assistants in the European parliament.