Former French president Nicolas Sarkozy and his wife, Carla Bruni-Sarkozy, enjoyed a taste of Canadian cottage life in the Laurentians last week, a respite from public attention that has been renewed by a French police raid on Mr. Sarkozy's offices and Ms. Bruni-Sarkozy's mansion as part of a probe into alleged secret campaign financing.

The latest twist in a long-simmering Affaire Bettencourt – a high-society scandal involving a billionaire heiress and secret recordings by her butler – is the first legal headache to hit Mr. Sarkozy after his presidential immunity expired on June 16, following his electoral defeat by François Hollande.

Tuesday's police searches came as an investigating judge and police look into allegations that a Sarkozy campaign treasurer accepted secret donations for the 2007 election campaign from France's wealthiest woman, Liliane Bettencourt, the 89-year-old heiress to the L'Oreal cosmetics fortune.

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On Tuesday, French media reported, judge Jean-Michel Gentil from Bordeaux and 10 officers from the brigade financière searched the office Mr. Sarkozy had been given as former president and the offices of Arnaud Claude & Associés, the law firm he co-founded and where he is expected to return to practice.

They also searched Ms. Bruni's hôtel particulier in Villa Montmorency, an enclave in Paris' 16th arrondissement, where the wealthy live behind streets closed off by wrought-iron gates.

The scandal began in 2007 when Ms. Bettencourt's estranged only child, Françoise Bettencourt-Meyers, went to court, alleging that a jet-setting photographer had befriended her mother and sweet-talked the elderly woman into giving him money, Picasso and Matisse paintings, and an island in the Seychelles.

The court heard that Ms. Bettencourt's butler, who said he was shocked at the way his frail, aging boss was treated by her confidants, had hidden a recorder in her drawing room and taped conversations between her and her advisers, including wealth manager Patrice de Maistre.

The recordings mentioned Florence Woerth, who was hired by Mr. De Maistre to help with the family finances. She was at the time the wife of Mr. Sarkozy's budget minister, Éric Woerth, who was treasurer for Mr. Sarkozy's right-wing UMP party during the 2007 election.

The Bettencourts' former accountant, Claire Thibout, alleged that politicians came to the Bettencourt home and received envelopes of illegal cash.

Mr. Sarkozy's lawyer had tried to forestall the raids by handing over his client's private agenda for 2007 to show that he only visited the Bettencourts once.

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Since losing office, Mr. Sarkozy has been reported to have vacationed in Morocco, then to have received an invitation to stay at a cottage owned by the Desmarais family in Morin-Heights, north of Montreal.

Mr. Sarkozy is known to be close to Power Corp. founder Paul Desmarais Sr. He has often been a guest at the Desmarais family's Sagard estate in Quebec's Charlevoix region and he awarded Mr. Desmarais the Grand-Croix de la Légion d'honneur, the highest honour ever bestowed on a Canadian by the French government, at a private ceremony in early 2008.

Around Lake Echo, with its stately log mansions and multi-level stone cottages and old-growth trees, Mr. Sarkozy and Ms. Bruni seem to have whistled through relatively unnoticed. (They are rumoured to have come and gone in the space of a few days last week.) Helicopters were seen loading and unloading passengers at what locals say is the compound where the Demarais family has two homes.

Of course, the neighbours add, helicopters aren't exactly a rare sight in the area, which had a turn as a vacation destination for Hollywood stars like Halle Berry, Michael Douglas and his wife and fellow movie star Catherine Zeta-Jones, and remains a refuge of the rich.

Rockers like Rush, Aerosmith and Black Sabbath have recorded on the lake, where motorboats are banned.

"The place is full of stars," said Norman Dussault, a long-time resident who once had Quebec comedian Yvon Deschamps over for beer.

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Legendary rocker Robert Charlebois lives in a home once owned by the Desmarais family, not far where Mr. Sarkozy reportedly vacationed. "If anyone would know if Carla was here, it would be Robert," said a neighbour.

Mr. Charlebois did not answer his doorbell.