It was thought they had been buried in a common grave in 1946, following the liberation of the city by the Allies two years earlier.
But the Strasbourg authorities confirmed many of the remains were, more than 70 years on, still being stored.
The discovery has raised serious concerns, with one organisation, which represents the UK Jewish community, stating that ‘serious questions’ needed to be asked.
A Board of Deputies of British Jews spokesman said: ‘This discovery raises serious questions about who knew about these remains and why they did not reveal this sooner.
‘We would expect a prompt and full investigation in to these matters, and the remains of these victims to be accorded a respectful burial in accordance with Jewish law as soon as possible.’