The #EuropeanParliament has a page on "Appropriate behaviour rules":
https://www.europarl.europa.eu/at-your-service/en/transparency/appropriate-behaviour

The Rules of Procedure, at Rule 10(1), state that:

«The conduct of Members shall be characterised by mutual respect and shall be based on the values and principles laid down in the Treaties, and particularly in the Charter of Fundamental Rights. Members shall respect Parliament’s dignity and shall not harm its reputation.»

https://www.europarl.europa.eu/doceo/document/RULES-9-2019-07-02-RULE-010_EN.html

Rule 176 deals with sanctions.
https://www.europarl.europa.eu/doceo/document/RULES-9-2019-07-02-RULE-176_EN.html