AFAIK, Eclipse, like most (all?) Java applications, uses UTF8 as its usual character set. Thus, it is not Eclipse that needs to be changed to enter French characters, but your operating system (in particular, the keyboard layout). It will probably be easier for you to figure out which escape sequences your OS uses to enter characters that are not represented on your keyboard. On Windows, you can do this using the Symbol Map utility, available in the Accessories section. I am not sure how to do this on other platforms.
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