because I didn’t found this in the first sight, and had to use a wmic query, I have prepared my Powershell command:
Get-WmiObject -Namespace root\microsoftdfs -Class dfsrreplicatedfolderinfo -Filter 'state=2' | Select-Object replicationgroupname,replicatedfoldername
The State 2 indicates, that the replication is not done yet, but a 4 would indicate that the initial replication is done.
See this website for the class explanation:
Possible states are:
Initial Sync (2)
Auto Recovery (3)
In Error (5)