I've three store views : default, de for German and fr for French.
I've translated all the files inside app\locale\en_US in above two languages.
I've placed the respective translated file inside de_DE app\locale\de_DE
for german translation and fr_FR app\locale\fr_FR
: french translation.
Cleared the cache, still the it's translation is not reflecting.
I tried manually deleting cache from var/cache
(this solution), but, is still not working.
Step by step :
Ps : Don't forget to save translated files with "UTF-8 Without BOM" option! ( if you aren't in China )