Europe's growing political risks are reviving a moribund corner of the credit market.

Trading in credit-default swaps tied to French, Italian and Dutch sovereign debt has surged this year as populist parties garner electoral support by bashing the euro and European Union. That's stemmed a long-term slump in trading of contracts insuring European government debt that was spurred by tougher regulations in 2012.

Swaps tied to French debt have posted some of the biggest trading increases, with weekly average volumes more than doubling this month versus January, to $1.1 billion, according to data from Depository Trust & Clearing Corp. Marine Le Pen, who leads in polls for the first round of France's presidential election in April, wants to break up the euro and replace it with new national currencies.