The Ossietzky price is awarded by the Norwegian branch of PEN. Carl von Ossietzky was the first Nobel Peace Prize recipient who wasn't able to receive his prize

The Ossietzky price is awarded by the Norwegian branch of PEN. Carl von Ossietzky was the first Nobel Peace Prize recipient who wasn't able to receive his prize in person (he was ill and imprisoned in Nazi Germany), so it's a symbolic point for them to award it in the same place Ossietzky would have received his price, i.e. in the town hall of Oslo.