Source: https://www.lg2g.info/legal-news-on/legal-news-on-foreigners-law/eu-citizes/1629-brexit-and-immigration-to-germany
Timestamp: 2019-04-25 15:43:29+00:00

Document:
The people’s voice in majority said „out“. So be it; this is nothing but a democratic decision. As it has been said, “When you’re out, you’re out.” No chance to change coaches anymore. Oh, I meant referendums anymore. How will this effect Brits right now in Germany? Will they be kicked out? May they stay? I want to briefly discuss legal consequences of the BREXIT for immigration – as of now. What rules will be applicable for future relocations? Nobody knows.
Britons and their non-European family members will lose their status as soon as BREXIT comes into effect because they do not belong to the European Union anymore. For those persons who are here on a temporary as well as a permanent status, the BREXIT withdraws the grounds for their legal sojourn under the free right of movement. Britons are then considered third country foreigners. They will require a residence permit pursuant to §4 I 1 AufenthG.
§51 I no. 1 AufenthG determines that a residence title expires once it loses its validity. Upon legal BREXIT, Brits will not have a residence title anymore. Pursuant to §50 AufenthG, persons are obliged to leave without undue delay after their permit expires. However, it is seriously to be expected that some kind of intertemporary provision will be issued for those living here now. Britons wanting to enter Germany will have to follow the general rules: apply for a visa from home or stand in line like all the rest.
So far the consequences can merely be predicted now. When suddenly millions of English, Scots, Wallisians, (northern) Irish have to leave their jobs and / or businesses, this will create an unbearable strain on the German economy. It can be assumed that those living here legally, will be able to continue to live here. We will now have to differentiate between those with a “temporary” and those on “permanent” status. Hence, it is to be expected that those persons living here already will not lose that status as such and can remain. The exact details are still to be negotiated.
Those persons on a temporary status can expect to continue as a normal third country nationals on grounds reflecting their reason to be here. A student will receive a permit to study at the university pursuant to §16 I AufenthG; an employee pursuant to §18 AufenthG, and a person in business based on §21 AufenthG. They will need a residence permit based on their reason to be here. It is imaginable that such first permits might be granted ex officio or under relaxed conditions. Later if a renewal is due, it can be assumed that they will be treated as a “ordinary” third country national.
Britons having had “permanent EU status” will presumably change from §4a FreizgG to §9 AufenthG – maintaining permanent residency. The difference between both kinds of permanent status is only hidden. The most important difference will be the time of permitted absence without jeopardizing one’s permanent status. Pursuant to §4a VIII FreizgG, Europeans are allowed to be outside of Germany temporarily for two consecutive years. Third country nationals only have a grace period of six consecutive months (§51 I no. 7 AufenthG) – both only for temporary purposes. So, if you have left for good then you are out for good.
Another major difference between “ordinary” and “European” foreigners lies in the status’ quality. In the event, German immigration authorities do not want a European inside of Germany, they have to cancel the European’s freedom of movement and possibly take the foreigner to court. Europeans conceptually have the right to be in Germany. So the threshold is high to do so. In contrast to that, “ordinary” foreigners have to combat the authority to remain in.
Better ask a fortune-teller than a lawyer. Britain’s Prime Minister has to formally give notice to the European Commission (art. 50 TFEU). then a two-year period starts where the Union and the UK have to come to a resolution on how the "divorce" will be realized. If nothing is negotiated inside that period, then EU membership automatically expires. And what until then? Simple. “Business as usual.” Legally nothing has changed yet. so far it is only the intention to give notice before really giving notice.
Oh, you are a dual citizen of UK and another EU country? You are concerned about the BREXIT issues? Forget your concerns! Forget them instantly. You have and will retain your EU status – based on the other citizenship. The same will be true for your non-EU dependents as they derive this status from you.
get Letters Of Interest from Germany-based business partners, if freelancing or self-employed, start working on your business plan.
N.B. This is the legal situation as of June 29, 2016. Updates will follow shortly after they are issued as law.

References: §4

§51
 §50
 §16
 §18
 §21
 §4
 §9
 §4