Start by putting the 2/ in a paragraph by itself in a paragraph above the red text in your example. Then pick a paragraph style that isn't used for anything else (or create a custom paragraph style).

Now modify that paragraph style to make its font size big eg 2.5x the size of the 'Autres style' in your screenshot. Now while you are modifying the style, go to Format > Frame and set the wrap around and left align.

Once you see the result, you can fiddle the size of the font for that style to get the top and bottom alignments dialled in. After that you just apply the style when you need that visual effect
Format Frame.png

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Andrew Lockton
Chrysalis Design, Melbourne Australia