voila la reponse que l'on ma donné sur un site anglais
[i]"An Illustrated Encylclopedia Of Uniforms Of The Napoleonic Wars" has these details for Prussian Dragoon regiments prior to the reforms of 1806.
Light Blue short tailed infantry style coat with the following distinctions.
Regt.No________Collar______Lapels_____Turnbacks
&Title__________&Cuffs
1.Graf Lottum____Black______White______Black
2.Mahlen________White______Pink_______White
3.Thun__________Pink_______Buff_______Pink
4.Gotzen________Buff_______Dark Red___Buff
5.Anspach______Dark Red___White______Dark Red
Bayreuth
6.Rohr then______White______None_______White
Von Auer
7.Borcke_______Scarlet_____Scarlet_____Scarlet
8.Esebeck______Scarlet_____None______Scarlet
9.Herzberg______Light______None_______Blue
_______________Blue
10.Manstein_____Orange____None_______Orange
11.Voss________Yellow_____Yellow______Yellow
12.Bruswitz______Black______Black______Black
13.Roquette_____Crimson____Crimson____Light Blue
14.Wobese______Buff_______Buff________Light Blue
The 1st, 2nd, 7th, 13th, &14th Regts. had yellow buttons, all the rest had white buttons.
The 8th & 9th Regts. had white laces to the buttons on their chests.
For 1806 the turnback colour might refer to an edging around the turnback which was the same Light Blue as the coat, the text is not entirely clear.
These details are for 1786 onwards, some of the regiment titles appear to have changed over time but there are no uniform changes listed until the reforms of 1806, after which there are only 6 Dragoon Regiments listed who wear the long skirted Kollet coat with the regimental distinctions shown in Carlo Antomio's 'Mont Saint Jean' link.
The first picture at top left of Carlo Antonio's first link shows the short tailed Dragoon coat (rather than the Kollet), but the ilustrations I have show it in a lighter shade of blue .
Dim 7 Nov - 15:58
merci beaucoup, c'est exactement se que je rechercher .