Cattleya walkeriana?
 

Looks like it but it would be easier to ID if we could see the plant.

I agree that it looks like one (alba) but it could be a hybrid. Did you loose the tag? Did you ever know what it was?

is the first time that it blooms, I bought it for Cattleya walkeriana

Oh! If you bought it as C. walkeriana var alba and it didnt come with a tag then I would say that that is probably what it is.

New pictures, it is fragrant
http://cattleyamasdevallia.wifeo.com...84b-Small-.JPG

http://cattleyamasdevallia.wifeo.com...78b-Small-.JPG

If the vendor said it was C. Walkeriana I would assume that it is. It has the classic Walkeriana shape. But I've seen many crosses that also inherit that shape flower so it's difficult to know for sure. Walkeriana is a great orchid because of it's compact foliage, nice size flowers and wonderful fragrance. Enjoy.

On other forums, I am told that this is not C. walkeriana

Do you have a photo of the plant with flower ???
For it to be walkeriana, the flower needs to be coming from a separate shoot directly from the rhyzome. If the flower is coming from the top of the pseudobulb its a hybrid and not the species walkeriana.

It is not walkeriana.