accents in the index

[jean]

I am an old Latex user but I begin using LyX 1.3.5 under Linux red hat 
to write a book in French (class book, french gutenberg). I have a 
problem with index entries that contain an accentutated letter. If i 
have to index the word "précision", I get in the index in the dvi 
"précision" and the exported latex file contains \index{précision}. 
But I click on the Idx button inside the text in the LyX window, I see 
"précision".
I just discover that in the exported HTML it is worse : the titles and 
some words in the text also are modified in the same way and in the 
index I now see "précision".

Did anybody ever see this phenomena?
Jean