Unfortunately, there isn't any information available yet on when the Redmi Note 5 will become available in European markets. It's been released in China, but there hasn't been an announcement regarding availability in Europe yet.
You can keep an eye out for announcements regarding the phone on Xiaomi's official website, as well as Amazon and other retailers that may eventually carry the device in Europe.
The best way to stay up to date is to follow Xiaomi's social media accounts and join their discussion forums. You can also occasionally search for any new updates related to the Redmi Note 5 in European markets.
In the meantime, you can take a look at our list of the Best Xiaomi Phones currently available on the market in Europe: