Bernard Madoff's alleged $50 billion investment fraud demonstrates the absolute necessity of better regulation of financial sectors, the French prime minister said Thursday.

Francois Fillon called the affair "a real scandal" and said it "clearly shows that the regulatory reform we've been calling for ... is absolutely necessary."

His comments on Europe-1 radio came after France's market regulator said late Wednesday that French investors may have lost "several hundred million euros" in the scam, through mutual funds with indirect exposure to Madoff's funds.

Madoff was arrested in the United States last week on charges that he carried out what he called a $50 billion Ponzi scheme that has left investors around the world in financial ruin.

Prosecutors say Madoff concocted the scheme to defraud investors, including the world's big banks and the rich and the famous.