The classic accounts of the battle hold that the French cavalry attacks were largely ineffective, with no Allied infantry squares broken, and I'm sure this was true on many occasions. However, as I read more about fighting near to La Haie Sainte I am struck by the number of successes of the cuirassiers in particular Chronologically, so far as I can tell, they caught the following troops in the open:
(i) the skirmishers of the 1st Light Battalion, KGL, prior to d'Erlon's attack
(ii) the Luneburg Battalion from Kielmansegge's Hannoverian Brigade and elements of the 2nd Light Battalion, KGL at some point during d'Erlon's attack
(iii) the 5th Line Battalion, KGL, led by Ompetda, as it tried to retake La Haie Sainte
(iv) the 8th Line Battalion, KGL, seemingly undertaking a similar manoeuvre
In addition, the 5th Line was also caught trying to move from line to square at an earlier point.
While this may not compare with the mauling given to d'Erlon's corps by the Allied heavy cavalry, it adds up to a brigade of Allied infantry (three battalions and elements of others).