Intense jockeying as left-wing rivals rush to unite. Accusations of betrayal as right-wing allies turn on one another. One party leader even briefly barricaded himself in his office.

In the days since President Emmanuel Macron of France stunned the country by dissolving the lower house of Parliament and calling snap elections, French politics have felt like a television drama on overdrive.

Parties are scrambling to forge alliances, align candidates and print leaflets for one of the shortest electoral campaigns in modern French history, with voting scheduled for June 30 and July 7. Candidacies have to be officially filed by Sunday evening.

The French president says he called the elections to respect the will of the people and to “clarify” the country’s political landscape after his party was battered in European parliamentary elections by a surging far right. He is now urging voters to reject extremes and embrace his centrist coalition.

Mr. Macron’s gamble has bewildered the electorate and forced political parties to confront long simmering internal tensions

To his political right, it has led to implosion. To his political left, it has fostered rare unity. Where it will ultimately leave him and his centrist alliance is unclear. The latest polls put the far-right National Rally party, led by Marine Le Pen and her protégé, Jordan Bardella, comfortably in the lead.