Hi Vincent thanks for posting and apologies for the delay! It looks like your question was already answered directly through a Support ticket but just in case anyone else is wondering the same thing: I would advise using our publish feature to share a Lucidchart document if the person you are trying to share with doesn't have a Lucid account. If you chose the publish to URL option (described in our Publishing article here) the viewer will have some ability to interact with the document (zooming panning around the canvas etc) without needing to log in at all. 

Unfortunately the viewer will not be able to see any Comments but they can click on Notes in the document.  I recommend taking a look at this Community post (in English) for an example of publishing in action. Hope this helps!