Where are Guard Posts? (Courtesan Guild Quest)

Well let me throw in my 2 bits if you look in the 2 camps surrounded by wooden posts near the barracks you always see 2 guards in full armor guarding a treasure chest killing them also works but it takes time.

There is a french outpost to the far north east (looks like theres a castle on the outer wall, its in front of that)

its the one the merc guy takes you to through a story mission

easy 8 kills a time there, wait for shift change, repeat

I've beat the game and I've been to those places and there are on guards any where

Within the game a guard post is considered a camp of the blue-clad guards (French soldiers), enclosed in walls made of wooden spikes. These posts are scattered all across the outer fields of Rome. If your having trouble locating them I recall there being one northeast of the Colosseum. I recommend simply shooting the crossbowman of their perches with your crossbow then subtly picking of the other guards while remaining undetected, this should complete the Courtesan quest. Again, these outposts are scattered across the outskirts of Rome (but mainly capagna) and are recognizable by their wooden walls. Also once the French general is killed (a story mission in aid of Bartolomeo) these soldiers will vanish, so complete it prior to that mission. Hope this helps.

If you completed the game the blue-clad guards (French soldiers) are not there anymore, just replay sequence 6 memory 2, you'll see lots of frensh guards. Try to shoot the guards with your crossbow and stay hidden so the guards cant spot you. Aim for the guards that are not walking.

If a guard is standing with his arms crossed blocking a path he is considered A guard.

I have found two guards posted in front of a treasure chest. If you go to the southern most part of the Antico District (which is the southern portion of the map) you'll find a doctor in a run down section up on a hill. If you face the doctor look sort of North-West and you'll see two sentry guards posted and standing still. The way I did it was I climbed up to the eagle perch and shot them from there. I know it's only two but it worked. After you shoot them go off to another part for a few minutes to give them time to re-spawn, then go back and do it again.