Breast plates only
I don't understand the ongoing discussion, it shows only a lack of understanding and ignoring sources.
the plate in Napoleon et l'Allemagne shows – Garde du Corps – which had no cuirass (but they were no cuirassiers but heavy cavalry).
It would be the same rediculous discussion to say French cuirassiers did not wear a cuirass because carabiniers of 1806 and grenadiers à cheval did not wear any.
The issue doesn't have to be shelved at all, the sources are there – either one can accept them or ignore them.
To repeat again, those regiments which were called cuirassiers did wear the cuirass, the other two heavy cavalry regiments
Garde du Corps
and
Karabiniers
did not wear any cuirass.
This is well reflected on all primary sources from 1791 to 1809.
The same for post 1810 – Garde du Coprs did not wear any cuirass but the Zastrow Kürassiere did very well wear one.
The tradition was kept.
It would be rediculous to argue that because Garde du Corps did not wear cuirass in 1810 – also Zastrow Kürassiere did not wear any.
In case one likes to see the non cuirass wearing heavy cavalry regiments in colour, follow the link of XV Brigada.
For more read :
Ortenburg & Kersten : Die Sächsische Armee von 1763 bis 1862, Beckum 1982
"Die beiden Kürassier Regimenter trugen schwarze Brustpanzer,
, page 16
The two cuirassier regiments (nota bene – 2 and not four) -did wear black front cuirasses.
From 1776 Saxony had only 4 heavy cavalry regiments
Carde du Coprs (no cuirass)
Karabinier Regiment (no cuirass)
Kürassier Regiment Kurfürst (cuirass, note Kürassier)WITH cuirass
Kürassier Regiment Prinz Eugen von Anhalt Dessau (1806 Kochtitky Kürassiere) WITH cuirass
In case one compares with an analytical mind primary sources you will find – surprise – surprise
immages of Saxon heavy cavalry without cuirass – these are
Garde du Coprs
Karabiniers
and Saxon heavy cavalry with cuirass – the Saxon cuirassiere.
So HistoryPhD – just paint your "Prussian" cuirassiers as
Garde du Corps and
Karabiniers
and call those units Saxon heavy cavalry.