PARIS — Europeans are quickly learning a lesson that Americans internalized years ago: They ignore Elon Musk at their peril. Until recently, Europe’s main challenge from Musk was mustering the means to enforce tech and trade rules on a billionaire mogul whose firms’ annual revenue exceed British or German yearly defense spending.

Elon Musk has been driving the news agenda in the UK and other European countries with often incendiary comments on X, prompting leaders to hit back.