This command will put you in observer mode, i.e. you become a spectator. The nation you were playing as becomes controlled by AI. Toggle observer mode off by running the command again, then use the tag command to start playing again.
The syntax for the observe command is as follows:
Find below working examples of the observe command.
The above command will toggle observer mode - note that you need to toggle observer mode off and use the tag command to start playing again.