EDIT: I found out myself :)

Edited 11/19/2016 16:08:31

There is an option to do this.

When creating a game go into the basic settings.
Here you'll find a part called "fog level".
If you select "Heavy Fog" you'll see your enemy next to you but you won't see how many armies he has on his territories.

The little picture on the left of those settings provides an example, so you can see what all fog-types do.