"We need to know how Britain sees its future relations with us," Merkel told the German parliament Thursday.
"Let there be no doubt: Brexit negotiations will demand a lot from Britain and Europe."
"A third-party state will not have the same rights or even superior rights to a member state," Merkel said ahead of a Brussels summit Saturday on Brexit.
"This may sound self-evident, but I have to say this because some in Britain seem to have illusions on this point," Merkel told the German parliament.
Britain has two years to complete its deal to leave the 28-nation European Union but is currently preoccupied with a snap election taking place in early June.