War refugees from Ukraine have the opportunity to work in Germany.
“People who had to leave Ukraine because of the war are granted a humanitarian residence permit for temporary protection according to § 24 Residence Act. The basis is the decision of the Council of the European Union in accordance with Directive 2001/55/EC of 04.03.2022.” https://www.bmi.bund.de/SharedDocs/faqs/EN/topics/ministry/ukraine-war-eng/faq-ukraine-artikel.html
When the residence permit is issued, the foreigners authority will already note in the residence title that gainful employment is permitted, even if there is no employment relationship in prospect yet. So no further work permit from another authority is required.
Until the official residence certificate can be issued and granted, the Aliens Department issues the applicant a so-called fictitious certificate. Even with this fictitious certificate, Ukrainian war refugees are allowed to work in Germany on a self-employed basis or as employees.
More information on the topic of work can be found here (also in Ukrainian): https://www.germany4ukraine.de/hilfeportal-en/labour-and-social-affairs
Responsible foreigners authorities can be found here: https://bamf-navi.bamf.de/de/Themen/Behoerden/?typ=ABH&
In Berlin, refugees can apply for their residence permit at the State Office for Immigration (LEA). All information about the application procedure at the LEA can be found here (also in Ukrainian): https://www.berlin.de/ukraine/en/arrive/online-application-temporary-residence-permit/