Hi,

> I've got an table (named "texte") with an column named "title" and the
> characterset is "NONE".

This is your problem. Charset "NONE" means that the database doesn't
know about the acutal charset you used to populate it. As a result, the
UPPER function only works for ASCII-Characters and not for the German
Umlauts.
You should never create a Database with Charset NONE unless you only
want to store character data as-is without the Database caring about the
actual contents.
Go here:
http://www.ibexpert.info/documentation/%20%202.%20Database/%20%208.%20Create%20Database/329.html
and look at the example on the bottom.
Unfortuately if you want to convert the data you already have in your
database you will have to "pump" everything over to a newly created
database with a default charset.

kind regards,
Michael