PARIS — Two weeks after taking office, President Emmanuel Macron, donning a white hard hat, stood before hundreds of employees at the nation’s largest shipyard, promising to protect a French jewel from falling into foreign hands.

As one of his first major acts, Mr. Macron vowed to review an imminent takeover of the shipyard, STX France, by an Italian competitor. “We’re an industrial power,” he told cheering workers, who had just completed building the world’s biggest luxury cruise liner of 2017, the Meraviglia. “We must guarantee the preservation of jobs.”

The government is now trying to defuse an uproar in Rome, days after blocking the deal and nationalizing STX.

Mr. Macron campaigned to make France more business friendly by luring foreign investment and easing regulatory complexities. But blocking the deal for STX, along with a series of other maneuvers in recent weeks, is prompting concerns that Mr. Macron may follow the tried and true French tradition of dirigisme — an interventionist approach that his predecessors have employed time and again to promote French interests.