The aim of the current regulations in Germany is to restore the traceability of infection chains so that an economic and social life as normal as possible can be resumed as quickly as possible. The aims of the governments in other countries are more or less identical.
The German government took its decisions based on a recommendation of the Leopoldina - Nationale Akademie der Wissenschaften, to introduce, starting from November 3rd, effective measures to reduce contacts by about 75%:
"The earlier this consistent reduction of contacts without protective measures is put in place, the shorter it can last, and the less psychological, social and economic collateral damage would be caused. With a drastic reduction of the contacts of every single one without protective measures to one fourth, it is possible to contain the pandemic (...) The aim must be to reduce the number of cases to such an extent that the health authorities can fully conduct contact follow-up again. As soon as this is possible, the restrictions can be cautiously relaxed without the immediate threat of another wave of pandemics."
(Link to the origial document (in German): https://www.leopoldina.org/presse-1/nachrichten/wissenschaftsorganisationen-zur-coronavirus-pandemie/)
The Chancellor and the Prime Ministers have agreed to review the effectiveness of these measures every two weeks (link to the video of the announcement at the press conference on October 28, 2020). The first evaluation took place on November, 16th. At the following press conference, Chancellor Merkel, Berlin Mayor Müller and Prime Minister of Bavaria Söder indicated that even more far-reaching measures can be expected at the meeting on November 25th. The measures taken so far have only led to a flattening of new infections, not to a sustainable reduction.