It's not true. Only Aussie Open have changed their surface. No reports of anything about the French Open. I'll continue to look though. They changed Paris Indoors to a slower hardcourt. That might be what you heard.
I mean you know this, but this is just a generic response now. Rome is easily the quickest of the major clay court events. The top surface layer of clay, is less than the other events. This plus the dry and warm weather conditions bake the court, giving it the extra speed and the ball bounces are higher.
When Sampras won Rome, it was very fast that year. At night is when Rome becomes slightly slower.