How can I make paragraphs at the event title? With the old Indico this was possible with HTML. Here unfortunately unsuccessful. Does anyone have a tip? Thanks
You cannot. The even title is text; no formatting is allowed there.
Or do you mean the event description instead?
No, I mean the title. In the old version of Indico it worked with
. Why not here anymore? I want to place a logo on the left and next to it a multiline title text.
Allowing it in legacy Indico was already a mistake… 
If you want to put a logo there, you can upload an event logo in the management area of the event, and/or use a custom stylesheet (depending on the event type) to hide the normal text title.
thanks for your help! 
Just to clarify this point: the main problem was that by allowing HTML into the title field we were “polluting” the metadata with markup and thus breaking the display in other places.
The best solution is to use the log upload feature and/or a CSS stylesheet as @ThiefMaster suggests.