These look like XML tags that are applied to the text in the InDesign document. As Steve has pointed out above, you can hide them by hiding the Tag Markers. If you want to get rid of them, you can choose View > Structure > Show Structure. This will show you all of the XML tags in the document. If you truly don't need them or they're causing a problem and you want to get rid of them, you can click on the root tag (the top most tag in the Structure panel) and choose Untag Element from the panel menu. You may need to repeat this step until all of the tags have been removed and if need be you can select multiple tags at once by shift + clicking, then choose Untag Element.
Your help is vermy much appreciated, thanks for the replies.
From what I've googled I also assumed it has something to do with XML Tags.
But somehow there is nothing showing up in the Structure Panel.
Whenever text is formatted, i.e. bold, a tag seems to get added invisibly.
This also happens when creating a new document from scratch.
It only seems to affect a few of my colleagues, my InDesign is fine. We are all running the same Machines, OS and CC Versions.
Can you see the "tags" (or whatever this is) if you open the Story Editor window in InDesign?
(Select some text and press CMD + Y when on a Mac and make sure that hidden characters are visible as you have shown in your first screen shot.)
Are you using IDML as exchange file format for the translation software?
The Story Editor ist showing pure text without any tags, but the different paragraph styles though.
Documents are exchanges as .indd as well as .idml, but I'm not sure what file the translation buerau is using - I'd guess idml.
If they are using IDML and getting the "tags", I'd have a look into the IDML file to see if anything is going wrong at your side.
Maybe a 3rd-party plug-in, that is injecting invisible code to the text when creating the IDML (or before).
Did you try to open the document with a "none-affected" InDesign and do you have the same effect with that version?
Then the tags are injected in the document itself.