The behaviour may be configured at two levels.
The user settings are read from the ~/.config/flake8 file. Example:
[flake8] ignore = E226,E302,E41 max-line-length = 160 exclude = tests/* max-complexity = 10
At the project level, a tox.ini file or a setup.cfg file is read if present. Only the first file is considered. If this file does not have a [flake8] section, no project specific configuration is loaded.
If the ignore option is not in the configuration and not in the arguments, only the error codes E123/E133, E226 and E241/E242 are ignored (see the warning and error codes).
This is a (likely incomplete) list of settings that can be used in your config file. In general, any settings that pep8 supports we also support and we add the ability to set max-complexity as well.