The heir to the Nina Ricci perfume and fashion fortune has been convicted of tax fraud by a Paris court after hiding millions in an offshore HSBC account.
Arlette Ricci, 73, was sentenced to a year in prison and ordered to pay a €1 million (£720,000;$1.1m) fine.
The court also confiscated two properties worth four million euros (£2.9m;$4.2m).
HSBC's Swiss private banking arm is being investigated after a leak revealed large scale tax fraud.
Ms Ricci, who can appeal, was given a two-year suspended sentence on top of her one-year custodial sentence.
Her daughter, Margot Vignat, 51, was also convicted and given an eight-month suspended sentence.
Ms Ricci was accused of hiding millions of euros from the French authorities to evade tax using an offshore HSBC account.
She was ordered by the court to pay millions in back taxes for the period of 2007-2009, with the exact amount to be set at a later date.
Ms Ricci's lawyer, Jean-Marc Fedida, claimed his client had been made an example of, calling her sentence "extremely severe".
Mr Fedida said he may ask the judge to let Ms Ricci serve the sentence under lenient conditions, such as partial liberty or wearing an electronic tag.
But telephone recordings quoted in court apparently showed that the perfume heiress was aware she was breaking the law.
In one phone conversation, she said, laughing, "I believe I did the right thing and I never heard from Bercy so all is well," referring to the French finance ministry.
"Yes, inevitably, necessarily because all that is illegal anyway," she said.
Ms Ricci, who has consistently denied the accusations against her, will now have to decide whether to appeal against her conviction.
She was the first of around 50 French nationals to face trial over tax evasion in the HSBC case. Her prosecution was seen as a test case for the so-called "Swissleaks" scandal.
A list of thousands of HSBC's clients was passed to the French government in 2009 by whistleblower Herve Falciani, a former employee of the bank's private operation in Switzerland.
But the bank's tax-evasion practices didn't come to light until the documents were reported by the BBC's Panorama programme and a host of other international media outlets in 2015.
Widespread media coverage led to criminal investigations in the US, France, Belgium and Argentina but not in the UK, where HSBC is based.
The UK's HM Revenue and Customs (HMRC) was given the leaked data in 2010 and identified 1,100 people from the list of 7,000 British clients who had not paid their taxes. But almost five years later, only one tax evader has been prosecuted.
In February, HSBC Group Chief Executive Stuart Gulliver admitted "unacceptable" practices had taken place at the bank's Swiss arm.