I am interested in the restrictions that apply to military persons that are also activate in politics, within the European Union.
Searching on this matter provides lots of results for US, but I could not find relevant information for EU countries.
E.g.: this article shows us "can do"s and "cannot do"s for US military personnel based on their active status. Random examples:
Can - Register, vote, and express a personal opinion on political candidates and issues, but not as a representative of the Armed Forces. Can - Join a political club and attend its meetings when not in uniform.
Cannot - Participate in partisan political fundraising activities, rallies, conventions (including making speeches in the course thereof), management of campaigns, or debates, either on one’s own behalf or on that of another, without respect to uniform or inference or appearance of official sponsorship, approval, or endorsement. Participation includes more than mere attendance as a spectator.
Cannot - Use official authority or influence to interfere with an election, affect the course or outcome of an election, solicit votes for a particular candidate or issue, or require or solicit political contributions from others.