Immigration lawyer

I would not tell someone that they shouldn't use a lawyer if they have reason to think that their case is especially complicated but the vast majority of people would manage without one. The rules are pretty straight forward and easy to find in the internet like on the German Immigration website BAMF. And the subject has been addressed MANY times on this site. But even marrying a German is not a guarantee of getting the visa.

If you marry a German, you will have to apply for the family reunion visa at the German consulate and produce the marriage certificate and documentation about who you are and what you do. And they will want to do some checking if it is a legitimate marriage and not just on paper. It requires that together you have a large enough accommodation and income to survive. You will also have to pass an A1 level German exam. You will have to gather all of these documents and some, if not all, will likely have to be officially translated into German by a certified translator. And of course one should be free of serious criminal convictions and swear that they are not a terrorist…

What I question is what a lawyer can do? You give him the papers and he gives them in and charges you money for doing so. Where a lawyer might be useful is if one is rejected for the visa. Say if one was once deported from the EU or overstayed a visa, then what circumstances might have led to a ban and what the consequences are might be negotiated or discussed.

Or where I have heard of people needing a lawyer was to get the documentation to marry. If people were married before then one needs to document that they are divorced or widowed but no longer married. I personally know someone who was married and divorced in Australia and then immigrated to Germany. He then married a Polish woman in Poland but the German authorities didn't want to recognize it as they said he didn't have the proper documents about the divorce.  They demanded a certificate that hadn't been used in Australia for more than a decade rather than the court decree he had. I'm not sure if he ever took a lawyer but I know it was unresolved for a couple of years and he then moved to Canada and had exactly the same problem for a couple of more years.