Filetable CONTAINS - search for MONEY/currency

I have a filetable ft_Doks with hundreds of pdf-files; most of them are digitally born.
Many of them are invoices.

Searching for text is more or less working, but it fails normally when I try to search for a currency value; e.g "62,71 €".
Also some text is problematic.
e.g. I have a term "Block mit Leimbindung": searching for "Block" works, while searching for "Leimbindung" does not

SELECT * from ft_Doks WHERE contains(file_stream, 'Leimbindung')

Can you help me?