Hi Sonja,
Here's another idea you may wish to consider.
You can use a nested substitute function to replace more than one character
in a cell at a time. I've only set it up for e (grave), e (acute), e
(circumflex), a (grave) and a (circumflex), but you can nest up to three
more. I think it limits it to 8.
if your data starts in A1, then in B1 enter
=SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(A3,"è","e"),"é","e"),"ê","e"),"â","a"),"à ","a")
and drag down..
Dave