Language Switching doesn't occur if url is entered in French having English store currently - in magento

I have difficulty that my current store is English & I am in category page but the thing is, that now if I write url's category.html part to it's french version then it gives an error of 404 page not found.

Ex. http://www.abcd.fr/r4-cards.html to htt开发者_运维问答p://www.abcd.fr/cartes-r4.html (From English to French View) - These are dummy urls so don't click to view!

Other thing is when I enter french url then the whole site should be converted in French view.

Any Help?

Please.

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I suggest you to rebuild indexes . if everything is set up properly this is a cache and old indexes issue