With no data to back this up, I think the Rafale is the stealthier design. The airframe as admitted by the designers is designed to be "discreet" rather than stealthy. It has certain stealth features which are obvious to the lay person, including some stealth shaping and some use of radar absorbent materials (RAM) but it's overall design hasn't been sacrificed to be totally stealthy. In addition it is designed as a "low emission" aircraft and it has that active cancellation thingy, (which may or may not be simply "marketing speak")...
The EF-2000 on the other hand does not appear to boast any "stealth" features at all in it's design to my eye at least and if it has any stealth features,, they are likely to be in the area of RAM and electronic emissions, rather than shaping. The EF-2000 does have one significant advantage though, it has recently demonstrated sustained super-cruising capability (ie: Supersonic speeds being achieved without the use of afterburner) at about Mach 1.3, which is only about Mach 0.2 slower than the F-22 has publicly demonstrated...
This of course has nothing to do with stealth, but does provide a significant air combat edge over the Rafale, which has to my knowledge, not yet publicly demonstrated any "super-cruising" capability... Cheers.