xC9 instead of É in xml file generated by Matlab

Hello !

I'm generating an xml file with Matlab by filling it according to an excel file.

xmlfile = fopen(file.xml, 'w');
fprintf(xmlfile, xmlString);

Where xmlString is a string which contains the all xml content. The problem is all É and é of my string are replace by xC9 and xE9 in the final xml file.

Is there a way to avoid that ?

(I put the '<?xml version="1.0" encoding="UTF-8"?>' at the start of the file of course)

Thanks for helping !