Here we need to distinguish the essence of the matter, which is the right to reside in Germany as provided by law or other regulations. Having such a right is an important step towards success. The second component is the formal-technical procedure: the rules for submitting an application, forms, evidence, competent authorities, and other bureaucracy. The formal side of the matter should not be underestimated; due to formal legal circumstances, quite promising cases may fail, when 'I have the right but cannot realize it.'
The basic principle requires a foreigner to apply for a residence permit in Germany through a German diplomatic mission in the country of residence. Germany, like other states, is interested in border control and selecting the foreigners whom the country allows to reside on its territory and enjoy the benefits of such residence. The Foreigners' Authority does not want to see uninvited foreigners who entered the country on visitor, business, and tourist visas, often issued by one of the Schengen Area countries. Very often, such foreigners, instead of sightseeing German attractions, begin to look for grounds to stay and reside in Germany. In such cases, the authority refers to the standard path of applying through a German diplomatic mission and advises the foreigner to return to their home country.
But usually every rule has exceptions (often quite numerous). I will name some of them, although this list will not be exhaustive, because solutions can always be found according to individual circumstances.
Foreigners who are already residing in Germany on some grounds and wish to change their status can apply to the Foreigners' Authority. For example, a student at a Berlin university, a Kazakh citizen Olga B., married a German citizen and now wants to change her residence status from a student visa to a family reunification visa. Of course, she does not need to travel to Kazakhstan for that to apply at the German embassy in Astana.
In some cases, citizens of countries that have the right to visa-free entry to Germany are exempt from applying through a German diplomatic mission, for example, citizens of Israel. It is often possible to enter Germany from Israel and apply on-site to German authorities for settling their affairs. Citizens of all CIS countries are subject to visa requirements.
German rules on legal relations of foreigners allow tourists with short-term visas to apply to the competent authorities if new circumstances have arisen after their arrival in Germany. What circumstances? Most often, it is the intention to marry or an illness. For example, Tatyana Petrova came to Germany for three months to visit her adult, married daughter. Shortly before the planned return, she became seriously ill and cannot leave Germany in time. Here, T. Petrova must apply for an extension of her visa at the German Foreigners' Authority.
Or, for example, Tatyana Petrova met a German citizen Nikolai Wagner, after a short conversation both realized they love each other and decided to get married immediately. Both quickly submitted the documents required for marriage registration, filed an application at the German registry office, and two days before the visa expiry actually got married. Such circumstances allow the resolution of all visa matters through local German authorities in Germany.
If Tatyana Petrova married Nikolai Wagner in her homeland, for example, in Irkutsk, then she cannot fly to Germany on a tourist visa, show the Russian marriage certificate, and demand a residence permit with her spouse in Germany. T. Petrova will have to apply for family reunification at the German Consulate General in Yekaterinburg.
Previously, the model of the so-called 'Danish marriage' was widely used. Simplified rules for marriage, especially with foreigners from far abroad, made Denmark a known country for marriage tourism. Employees of Danish registry offices near the border usually speak German well and quickly, without excessive bureaucracy, process the marriage between a German resident and a foreigner. For this, the foreigner did not even have to visit Germany; it was enough to enter Denmark with a Schengen visa.
'Danish marriages' are quite legal and effective, because EU countries are obliged to mutually recognize documents of each EU member. After the marriage, the couple applied to the Foreigners' Authority for a permit for the foreign spouse to reside in Germany. The Foreigners' Authority was, to put it mildly, unhappy with the unexpected, quite numerous appearances on their doorstep of German citizens with a newly acquired foreign spouse in tow.
As a result, several years ago the Federal Administrative Court significantly reduced the flow to obtaining a visa through the 'Danish marriage' without the foreign spouse returning to their home country. Now the 'Danish marriage' works for residents of Germany intending to marry under the simplified procedure. Foreign residents in some cases can still use the 'Danish marriage' option today.
T. PUE, German lawyer.