Think you're getting confused, because you can get halogen projectors.
If the question was 'what is the difference between reflector VS projector headlgihts:' then the answer would be as follows:
Reflector lights work by bouncing light around a concave reflector.
Projector lights work by bouncing light through a 'fish bowl' type lens which focusses the beam.
Clios can come with either halogen reflectors, halogen projectors, and xenon projectors.