The 73-year-old granddaughter of fashion designer Nina Ricci was among thousands of clients of HSBC's Swiss private bank unit whose names were leaked to French authorities in the so-called "SwissLeaks" scandal. Other trials are expected to follow.
The Paris court said Arlette Ricci hid more than 20 million euros that she inherited from French tax authorities, also using accounts based in Panama.
Ricci was convicted of tax evasion and money laundering Monday and sentenced to three years in prison, with two of them suspended.
The judge also ruled for properties in Paris and Corsica to be confiscated.
Ricci was not present for the verdict. Her lawyer Jean-Marc Fedida told reporters that he is deciding whether to appeal.
HSBC's Swiss subsidiary is being pursued by French authorities who suspect it of large-scale tax fraud. The bank was ordered last week to post a bail bond of 1 billion euros to cover possible fines.