Text paragraph width

Is the language set to French or French: Canadian?

Does enabling Hyphenate make a difference? Many people don't care for hyphenation, but the purpose of hyphenatation on body text is to reduce the rag on the right hand side.

How many characters, on average, do you have per line?

~Barb 

The Paragraph Composer (usually) provides more balanced line endings within a paragraph (see the lower part of your example).

And you can optimize the "holes" even further. But there is no general setting for this. There are many "screws that can be turned".

I tried with Lorem ipsum text, but it was not the same. So I cropped a part of the text to show the right border only. Following all good info I'm getting in this post, I tried to change the "Composer" setting. I noticed a difference between "Adobe Paragraph and Single-line composer" It seems that "singl-line" makes a better job. I was wondering if the French text could be an issue for this kind of problem? 

Image removed by the moderator 

It could be a number of possible issues. Does the text have a right indent? Have you used non-breaking spaces? Do you have character styles applied--either manually or automatically?

As pixxxelschubser suggested, you really need to replace the sensitive text and show examples and post a sample document. Otherwise, it's a guessing game.

The Justification and Hyphenation variable combinations are enormous:

If you replace your text with placeholder text (with the formatting structure preserved), does the unwanted behavior persist? If so, show us a screenshot of this document or upload this file and link here.

(And we don't need the whole document - a page or two is perfectly fine.)

So many possibilities!

We have also seen documents with GREP styles—automatically assigning No Break on the fly—that were created by a previous user that are impacting the layout for the person who inherited the document. Once you find them, you can modify or remove them. 

Option 1: we gave you an idea of where to look and you can fix it yourself

Option 2: start sharing screen shots so that we can see what is going on

Option 3: share your file—you can put it on dropbox and post the link here (public) or message me directly (private) by clicking my avatar above this reply.

~Barb

The paragraph’s Justification, Composer (Single Line or Paragraph), Hyphenation and Balance Ragged Lines settings, all have a cumulative affect on how lines break. 

Please show us your paragraph style settings

and a screenshot of the behaviour in your document.