Looking at how the letters are different - compare all the A's and the E's - I'd say it's handwriting, not a font

I'm not sure. It seems to be several versions of letters : two 'S', two 'A' ... R are the same, T too... Possible?

This is a font made by Ségolène Ferté from the original lettering of Blacksad with alternates and ligatures. Keep searchin'...