If no country tag is specified, this command toggles (enables and disables) occupation painting. If the country tag argument is provided, your country will occupy all land that the specified country owns (but not land that they only occupy).
occupationpaint [country tag]
|Country Tag||Optional. If you provide a country tag here, this will occupy all land that the specified country owns.|
One of the two ways this command can be executed - this will toggle occupation painting.
Executing the above command would claim all of Germany's (GER) land for your country. To clarify, this will claim land that they own, not land that they solely occupy.