I've worked a fair amount of relocation homes and I'd say be agressive. They won't always deal, but often they will. They typically don't want to hold on to the house and will take a little less than fair market value. They've typically calculated this in to the HR costs of moving a person or will charge it back to that department. It always depends on the home though. It depends on the area, the condition, the number of showings, and so many other factors.
Are you working with a buyers agent? If not and you are looking in the DFW area I'd like to help. If you're really working in Paris I can refer you to one of my excellent partners there.
Prudential Texas Properties