(Reuters) - Former French President Nicolas Sarkozy was placed under formal investigation on Thursday in relation to a case involving L'Oreal heiress Liliane Bettencourt, a judicial source said.
The source said the former president was being investigated for taking advantage of a vulnerable person.
Sarkozy has repeatedly denied taking campaign funds from Bettencourt, France's richest woman.
(Reporting by John Irish; Editing by Sophie Hares)
