Socialist former French Prime Minister Manuel Valls was informed that he must join President-elect Emmanuel Macron’s En March! Party if he wants to run under its banner in June’s parliamentary elections.

“As of today, he (Valls) does not fit the criteria that would allow the investiture committee to take him on, so…, (until he joins) the national investiture committee that I preside over cannot consider the candidature of Mr. Valls,” Jean-Paul Delevoye, who chooses Macron’s party’s candidates, told Europe 1 radio on Wednesday.

The news sends a signal to politicians to the left and right of Macron’s year-old Republic on the Move party that they cannot sit on the fence as they seek to position themselves for the June elections that will complete the political landscape for the next five years.

Some, like Valls, want to be part of a Macron majority, but others are preparing for opposition, while the main center-right grouping The Republicans hopes to force the independent centrist into a coalition.

Valls, a high-profile politician on the pro-business right of the Socialist party, said on Tuesday he was interested in joining Macron – a move that has angered Socialist colleagues who are trying to prepare to fight the legislative elections after taking a beating in the vote for president.

Macron served as economy minister in a Socialist government under Valls, but left to make his successful bid for president at the head of his own start-up party.

Though Macron’s party does not have any members in the current parliament, Macron and his aides are hoping to secure a majority in June to allow him to push through economic reforms to revive an economy beset by high unemployment and sluggish growth.

Macron’s camp has said the names of Macron’s 577 candidates for the legislative elections will be announced on Thursday.

Macron’s team is being careful not to favor either side too heavily, and is especially wary of appearing too close to the deeply unpopular outgoing Socialist government.

The Republicans, the main center-right party whose candidate like that of the Socialists was eliminated in a first vote for president on April 23, were preparing on Wednesday to unveil a policy platform that softens some of the hardline measures it was proposing during the presidential campaign.

French President Francois Hollande will formally hand power to his newly elected successor Emmanuel Macron at 10 am local time (0800 GMT) on Sunday, according to an official source.

Meanwhile, as part of the continuing changes in French politics, top Socialist Hamon announced that he will launch new leftwing movement.

Hamon, who finished fifth in the first round of the election in April, said he invited members of any party to join him and “rebuild the left”, although he will remain a member of the crisis-hit governing Socialist Party.

The announcement came after Valls had declared that France’s Socialist party “is dead” and later saying he wants to run in favor of Macron’s party.

Failed French presidential candidate Marine Le Pen’s niece Marion Marechal-Le Pen has decided not to stand for re-election in June’s legislative elections, a move that lays bare the divisions in the party.

The 27-year-old, one of only two National Front (FN) lawmakers in the outgoing parliament and a popular figure among the party faithful, said in a letter to the Le Dauphine Libere newspaper that she would be leaving political life for a while for personal and political reasons.

Marechal-Le Pen, whom some in the party hope will eventually take over from her aunt, and who always gets loud applause at party rallies, is more conservative on social and economic issues.

“This raises a lot of questions on how the party will evolve,” said Joel Gombin, a specialist of the FN at the Jean Jaures research institute. “It risks leaving a number of people orphan, and could trigger some fighting among those would like to take over from her at the head of the ultra-conservative faction of the FN.”

If Le Pen did run in the parliamentary elections and lost “things could get complicated for her,” Gombin said, adding that this could harm her capacity to make the FN evolve as she likes.

After losing to Macron on Sunday, Le Pen said she wanted to transform the party, while other party officials said an alternative name was being considered.