French police and investigators raided the offices and home of far-right National Front party founder Jean-Marie Le Pen on Wednesday searching for evidence of alleged tax evasion through foreign bank accounts.
Le Pen, 87, contacted by Reuters while on a trip abroad, flatly denied any wrongdoing.
A French news website has said he had a hidden account in Switzerland managed by an associate.
"I am stunned and infuriated, I do not see what justified such a search," he said by telephone. "I have no secret bank account abroad."
Two other searches were conducted as part of the same inquiry at the homes of a current and a former assistant of Le Pen, a source in the French judiciary said.
Le Pen was expelled earlier this year from the party that he founded after a feud with his daughter Marine, who is now leader of the anti-immigrant, anti-EU party and set to run for president of France in 2017.
That followed remarks in which he repeated declarations that the Nazi gas chambers were a "detail" of World War II history.
Marine Le Pen has broadened support for the party by shedding the Front's anti-Semitic image and focusing more on issues such as unemployment.
The search of Le Pen's home was one of several operations that sparked political ire this week against independent judicial investigators in France.
Former President Nicolas Sarkozy on Wednesday said the country would do better spending money to monitor potential terrorists than tracking political leaders like himself.
An official investigator looking into an international cocaine-smuggling operation has ordered checks on Sarkozy's phone usage, a move the former president said could not be justified simply because he had used the services of the same airline company as the one at the center of the drugs probe.