President Emmanuel Macron threw French politics into disarray on Sunday when he unexpectedly called for snap elections.

The surprise move came after his party was battered by the far right in European Parliament elections. Mr. Macron dissolved the lower house of France’s Parliament and said the first round of legislative elections would be held on June 30.

France now finds itself in unpredictable territory, with the future of Mr. Macron’s second term potentially at stake. With less than a month to go before the poll, parties are now scrambling to field candidates, hone their messaging and, in some cases, forge alliances.

Here is what you need to know about the snap election.

What happened?

France’s far-right, anti-immigrant National Rally party, led by Marine Le Pen and her wildly popular protégé, Jordan Bardella, surged to first place in elections for the European Parliament on Sunday with about 31.4 percent of the vote. Mr. Macron’s centrist Renaissance party came in a distant second, with about 14.6 percent.

Mr. Macron acknowledged the crushing defeat in a televised broadcast to the nation that night.

“France needs a clear majority to move forward with serenity and harmony,” Mr. Macron said, explaining why he had decided to call for legislative elections.