The French ammunition is THV, standing for Trés Haute Vitesse, or Very High Speed. It's made of brass bar stock, cut to length, sized for caliber, and lathe-turned to a sharp point on a tapering cone. It has incredible velocities. A test was done in South Africa during the 1980's: the 9mm. Parabellum chronographed over 1,900 fps, and the .357 Magnum over 2,500 fps. It would defeat any vest, up to and including Level 4. For this reason, it's been banned in many countries. I understand that France has now declared this a "war munition", available for sale only to national defence forces or law enforcement bodies (with appropriate export permits and licences).
As far as penetration goes, the THV will penetrate very well in the first part of its travel, but because it's very light, it loses velocity quickly. It's very likely to stay within the body of a felon, because it doesn't have the momentum to over-penetrate. In this sense, it's a very good stopping round indeed: it tends to dump all its energy into the target, rather than waste a lot of it beyond the target in flying downrange. "Field tests" (euphemism for police use) showed it to be pretty effective in bringing down BG's: not necessarily as good as (say) a 125gr. .357 Magnum hollowpoint, but at least as good as a 9mm. 115gr. +P round.
Of course, it's very easy to make your own THV equivalent: just get good brass bar stock of almost the right diameter, then lathe-turn it to (say) .357" diameter, cut the cone and sharp point, and then cut off at the appropriate length. For loading, use a very fast powder (I seem to recall that the factory THV loads used a shotgun powder), but watch that pressure spike! - it's very hairy indeed at these velocities in a handgun... (The THV cases, even factory loads, were always full of over-pressure signs: primers weren't just flattened, they flowed!) In South Africa, dozens of tool-handy gun owners made their own THV rounds while the "craze" lasted, and they all seemed to perform pretty well. One thing, though: make sure that there's enough bearing area for the bullet to grip the rifling and stabilize. Some guys tried to have a very short bearing area, in the interests of reducing bullet weight and increasing velocity. This led to unstabilized bullets key-holing all over the target - not a good thing for penetration...
