There is mostly private CCTV (inside homes, banks, stores, etc.) and users are not allowed to capture public ground. Public CCTV can mostly be found in public transport, high-risk areas, some traffic hotspots and each individual state has their own laws, police is not allowed to transmit real time CCTV. Here‘s an article about it (it‘s mainly about Berlin but it’s pretty much the same situation in Hamburg whereas regions like Bavaria give police more freedom):
https://www.theguardian.com/world/2016/dec/21/germany-to-expand-cctv-network
„Laws in Germany around the use of surveillance cameras are more restrictive than in many other countries and, even though Monday’s attack took place on one of the busiest squares in the city, no footage of the incident has yet been made public.
The proposed new laws will allow for an increased use of CCTV in public places such as sports stadiums and shopping centres, as well as forcing data protection commissioners to give greater weight than before to “the protection of life, health and freedom” when deciding whether to permit video surveillance.“
And:
„While the new legislation would represent a relaxation of the country’s strict privacy laws, the power to allow or to ban CCTV cameras in public spaces remains with Germany’s states and city states.
Only the regions of Bavaria, Baden-Württemberg, Hesse, Saxony and Saarland allow the use of surveillance cameras in “public places”, a definition that does not cover railway stations or public transport.
In Berlin, there are almost 15,000 CCTV cameras installed on vehicles, about 3,200 of which can be switched to live transmission. But data privacy regulations stop the police from installing cameras in public spaces that transmit images in real time.
In June, Berlin’s then interior minister tried to change local law to allow CCTV surveillance of crime hotspots such as Alexanderplatz and Kottbusser Tor in Kreuzberg. But the proposal failed partly because of a last-minute intervention by the Pirate party, which entered the state parliament in 2011 on a data protection agenda.
The city’s police union argues that restrictions put its officers at a disadvantage compared with those in regions such as Bavaria, where they can set up mobile CCTV units.“