A French concert pianist won a six-year fight to get back money she lost to Bernard Madoff’s Ponzi scheme after a Luxembourg appeals court said her bank committed a substantial error when advising her about the investment.

Banque Internationale a Luxembourg SA must pay 250,000 euros ($277,000), plus interest dating back to 2010, the Luxembourg Court of Appeal ruled, according to a copy of the judgment. The bank failed to highlight the “clearly exorbitant, exceptional risks” the client took by investing in an unregulated hedge fund.

“The bank can’t hide behind the signature” of the unidentified woman “of a waiver that was pre-drafted in language that was technically correct and comprehensible to people with some knowledge in the economic and financial area, but inappropriate when it comes to a concert pianist,” the court said in the Feb. 4 decision.

BIL, which was a Dexia unit at the time, is one of several lenders that have been sued over their role as custodian banks for Madoff-linked funds. Pierre Reuter, the lawyer for the French woman and investors in other Madoff-related lawsuits, said the ruling is a rare win for investors in Luxembourg.

“This is an important decision because it strengthens the rights of investors with their individual bankers,” Reuter said.

A spokesman for BIL declined to immediately comment.

While the court rejected claims that the bank had intentionally deceived the client, it ruled the bank committed a “substantial error” by allowing the pianist to sign a waiver for placing her funds “without explaining to her in terms adapted to her low level of economic and financial knowledge, the inherent risks of investing in alternative investment products.”

More than seven years after Madoff’s massive Ponzi scheme was uncovered, recovery efforts by lawyers representing European victims have progressed slowly. UBS Group AG and HSBC Holdings Plc are among defendants in dozens of Luxembourg lawsuits filed by investors who lost millions of dollars, holding the banks liable for their role as custodians overseeing deposits and payments in individual funds linked to Madoff.

Madoff pleaded guilty in 2009 and was sentenced to 150 years in prison for using money from new clients to pay earlier investors.