OK at lecturing
You can email him 50 times about the same topic, 99% will not reply. If you are female, the odds of getting a response will be higher... Essay feedback is unbelievably poor. For 50% of your grade, expect NO feedback at all, as Dumay cares only about giving an arbitrary number and not helping the students to actually learn. The harder you try in his classes, the more waste of time it is for the student. Watching sesame street will give you more feedback on your work than any input from Dumay.
good lecturer and nice accent
Zero feedback and odd bias for female students - expect a slower turnaround than other lecturers. If you're going to take a month at least give some reasoning supporting my marks!