Downloaded OS X Yosemite, I don't have the application "Photos"

I downloaded OS X Yosemite, I don't have the application "Photos". what should I do?

The update was successful, but once I finished the iPhoto logo is crossed with a prohibited direction.

I click on it and I have a message: "to open iPhoto, you must upgrade to the latest latest version"

So I click on "search the APP Store" and then the app store opens and I have a message: "Article not available: the article you are looking for is not available on the french store".

I searched the internet and learned that iPhoto is replaced by photos from the update.

I see in my mac if this application and nothing, I type in the app store and nothing.

What should I do? I'm desperate.

Thank you in advance

Laeti1712