Yes, if your course is scheduled to finish during the ongoing summer semester. Proof of degree(s) or course achievements of the ongoing semester can be submitted at a later point. In this case please attach an official confirmation from your higher education institution regarding the expected completion date of your current course or an up to date record of your course achievements (Transcript of Records). Furthermore, your transcript has to incorporate a final/average grade - please take note of the hints and rules for the application process via the website "Application Procedure for Consecutive Master Programs at Freie Universität Berlin".
This, however, does not exempt you from handing in the official final degree certificate after your course has finished. You have to submit your graduation certificate/ diploma during the first master semester in the enrollment office - otherwise your (preliminary) license is rendered invalid.