Wii I have a black and white image?

the wii outputs in PAL signal and French TVs operate in SECAM. this conversion results in a black and white image.

it is also possible that the pirated version of the game you downloaded is a NTSC (USA) version and this also produces a black and white image.

in both cases, it is possible to fix the problem.
1st case - read your TV manual
2nd case - search on google

yes yes we also tried connecting directly to the TV, but it still doesn't work because it then removes the image from the TV if I understand correctly what I was told...

because we already have a similar cable plugged into the TV I think it's from the Voo connected to the TV

Oh really... Sorry but I don't see what it could be due to...
You can just bring it back to the store since you bought it yesterday...
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hummm donuts

good life attitude

Try to disconnect all the wires from your Wii, otherwise try those from your TV. If it still doesn't work, take the game back to the seller.

Well, there, at the back or on the side, where you need to plug in the yellow, white, and red cables.
You look and plug in according to the colors.
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hummm donuts

good life attitude

Well, here is the solution to your problem. If you don't have a yellow output, it's normal that it's in black and white.

You need to check in the box of your Wii; you should have a kind of adapter where you can plug in the three colors. It looks like this: http://img.game.co.uk/images/gameware/phonoscartadaptor.gif
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Hmmm donuts

Good life attitude