Tag president jean claude juncker
I think you meant to say "tag @JeanClaudeJuncker"!
Jean-Claude Juncker is a former President of the European Commission, serving from 2014 to 2019. He is a Luxembourgish politician who has held various positions in the European Union, including Prime Minister of Luxembourg and President of the European Commission.
If you're looking to tag him on social media, you can use the handle @JeanClaudeJuncker.