Former president Nicolas Sarkozy has been charged with taking financial advantage of France's richest woman as part of a probe into illegal party funding, a move that supporters say is aimed at preventing his political comeback.
The 58-year-old Sarkozy -- who this month made the strongest hint yet that he could be a presidential candidate in 2017 -- has repeatedly denied claims he accepted cash-stuffed envelopes from Liliane Bettencourt to fund his successful 2007 campaign.
Bettencourt, the world's richest woman and heiress to the L'Oreal cosmetics empire, is now 90. Medical experts say her mental capacity began to deteriorate from the autumn of 2006.
Sarkozy's lawyer Thierry Herzog said his client "considers the treatment inflicted upon him as scandalous" and that they would appeal the "unfair and incoherent" decision by judge Jean-Michel Gentil, who is in charge of the case.
Sarkozy was unexpectedly summoned Thursday to the Bordeaux offices of Gentil for direct encounters with at least four former members of Bettencourt's staff.
Gentil was seeking to establish how many times Sarkozy had visited Bettencourt during his successful campaign.
The former president has always maintained that he visited her home only once during the campaign, to meet her late husband. Members of her staff have, however, contradicted his version of events.
Bettencourt's former accountant, Claire Thibout, told police in 2010 she had handed envelopes filled with cash to Bettencourt's right-hand man, Patrice de Maistre, on the understanding it was to be passed on to Sarkozy's campaign treasurer, Eric Woerth. Woerth has already been charged in the affair.
Investigators suspect up to four million euros ($5.2 million) of Bettencourt's cash subsequently made its way into the coffers of Sarkozy's UMP party.
Gentil and two other examining magistrates had spent 12 hours questioning Sarkozy in November. They decided not to formally charge him then but to continue investigating the allegations.
France's legal system has nothing that exactly matches the charges or indictments brought in English or US courts; but an investigating judge's decision to place someone under judicial investigation is the closest equivalent.
Sarkozy faces allegations of obtaining significant amounts of money from Bettencourt, breaching electoral spending limits and taking advantage of a person weakened by ill health.
Brice Hortefeux, a former minister in the Sarkozy government, denounced the move, saying it came at a time "when dozens of opinion polls show... clearly and strongly that there is a growing confidence in Nicolas Sarkozy."
Hortefeux, who heads the association "The Friends of Nicolas Sarkozy", deplored Friday that "some people are being hounded all the time."
Sarkozy's former prime minister Francois Fillon added: "I am astounded by this decision to charge him, which seems to me to be as unjust as it is excessive."
Sarkozy lost immunity from prosecution when he was defeated in the 2012 presidential election by Socialist Francois Hollande.
Anyone convicted of exploiting a person's weakened mental state can be punished by up to three years in jail, fined up to 375,000 euros ($484,000), and banned from holding public office for up to five years.
French judges have already successfully pursued Sarkozy's predecessor as president, Jacques Chirac, who was convicted in 2011 on corruption charges related to his time as mayor of Paris.
Chirac, excused from attending his trial because of ill health, received a two-year suspended prison term.
Since losing to Hollande, Sarkozy has concentrated on making money on the international conference circuit, but he has repeatedly hinted that he is considering another tilt at the presidency in 2017.
Earlier this month, he told Valeurs Actuelles magazine that his "sense of duty" to his country could see him return to the political arena. Sarkozy's UMP party is caught in a leadership battle and many view him as a unifying figure.