The new buzzword to beat  in France is l’entrisme — as in “entryway.” It’s the politically correct euphemism to describe the infiltration of a resolutely secular French political space and broader society by radical elements — namely the Muslim Brotherhood. 

With issues like antisemitic attacks, school violence, and immigration looming ahead of European parliamentary elections in June, the entry of radical Islamic discourse into the life of the country is seen as increasingly troubling. That is something the National Rally of Marine Le Pen and rising star Jordan Bardella have warned about for a long time.

Now President Macron appears to be recognizing the dangers, albeit belatedly. In his latest defense council meeting on Friday, Monsieur Macron requested a report on the state of the threat that is currently posed by the Muslim Brotherhood and its acolytes in France. His interior minister, Gérald Darmanin, stated afterward that mounting an effective offensive against “Islamism” would require “a shock” in the country.

The first such shock came in the form of a recent clampdown by the courts on any public speech that tries to condone Hamas’s October 7 attack against Israel or to frame Hamas as a resistance movement. Doing so is now tantamount, legally, to condoning terrorism. Offenders can face up to seven years’ imprisonment. 

The Wall Street Journal reported that French prosecutors are now investigating politicians on the far left, union officials, and hundreds of other people “for allegedly condoning terrorism and inciting antisemitism since October.”

Even though turmoil in the Middle East has exacerbated violence against French citizens — particularly against Jewish ones — Western Europe’s biggest country has struggled with Islamic extremism for years. The  Islamist attacks at Paris of November 2015 and the deadly attack on the offices of a satirical magazine before that left lasting scars. 

It is notable that Mr. Macron brought in the tough-talking Monsieur Darmanin, along with a former ambassador to Algeria, François Gouyette, to draft an initial report on the Muslim Brotherhood threat in France. That report may not come before September, but placing the issue on the top of a crowded domestic agenda may aim to galvanize awareness among local elected officials.

They are sometimes slow to react to potentially criminal incidents in which radical Islam may play  a supporting role. The problem is not just with Paris. A French intelligence “note” that was reported in various French newspapers in recent days points to the region of Isère and its capital, Grenoble, as a “laboratory of Islamist offensives” that is now being confronted with a “strong Brotherhood activism.” 

According to the intelligence note, a trio of locals born respectively in Algeria, Tunisia, and France have been trying for years to infiltrate local Muslim authorities. Having made a headquarters of sorts from the “great mosque of Echirolles,” described as “the main nerve center of Isère Brotherhood,” they seek in various ways to impose their dogmatic reading of Islam across the wider region.

So it appears that the radical Islamic “entryway” is occurring both on and far away from the Champs-Élysées. It could be that Mr. Macron, by taking a tougher line against the radicals, wishes to steal some thunder from the National Rally, which is surging ahead of Mr. Macron’s flailing Renaissance party in virtually every poll.

With five weeks to go before the vote for the European parliament on June 9, Mr. Bardella’s conservative party list is well ahead of Mr. Macron’s center-left coalition of European candidates: 32 percent versus 17 percent, according to the latest Ipsos/Le Monde poll. As if to underscore that gap, Mr. Macron’s lead coalition candidate,  Valérie Hayer, performed poorly in a televised debate last week with Mr. Bardella. 

An even bigger debate is coming in the days ahead when Mr. Bardella, who is Ms. Le Pen’s telegenic protégé, will face off with France’s meek prime minister, Gabriel Attal, whose role in the European parliamentary elections next month may not be insignificant. This will be yet another kind of  “entrism” — something akin to a lean shark entering a fish tank occupied by a tasty halibut. 

Few if any French voters are happy about radical Islam entering into the public life of their nation, forged as it was in secular traditions. Look for Mr. Bardella to sink his teeth, on national television, into Mr. Attal over attempts to stamp out a toxic Islamism that he will aim to portray as too little action, too late.