There is one single catalogue page on Perlora in the WMF book; there are 4 platters: 21, 22, 24,5 and 30 cm. All of these are deeper and considerably thicker than your dish. The range of colours is limited to green, topas and goldruby - and wmf green is dark. So I am tempted to say: not Perlora.
These plates are not technically difficult, so it will probably remain unattributed. My first thought was Joska who did a lot of this type of work - but then again, so did a lot of other firms...