The publication fee will be covered only if a Freie Universität member is responsible for the settlement of the fee as "submitting" or "corresponding author." The author must be a Freie Universität member at the time when payment is made (§ 43 Berliner Hochschulgesetz).
Yes. Everybody officially pursuing doctoral studies at a university in Berlin is a member of that university according to section 43(5) of the law governing higher education in Berlin (Gesetz über die Hochschulen im Land Berlin, BerlHG). Consequently, you can apply, as long as your article is in keeping with the conditions set forth for funding by the German Resarch Foundation (DFG).
Conditions for funding
The relevant question is only whether the publishing journal is a "genuine" open-access journal. As a rule, such a journal will be listed on http://www.doaj.org/. It is of no importance through which additional websites the article is channeled.
Even if journals have not (yet) been registered with the DOAJ, publication fees can be covered through the publication fund. In all cases, journals must be genuine open-access journals, and according to the German Research Foundation's regulations, they must have strict quality-assurance procedures in place.
The critical factor is the invoice date. Funding is allowed only for fees invoiced during the current financial year. Please make sure that all invoices of 2020 are submitted to us by the end of January 2021. Applications which are submitted after 31st of January can not be considered for funding.
The financial year 2021 starts on 1st February 2021.