  To advance from milli-arcsecond to micro-arcsecond astrometry, time keeping
capability and its comparison among different stations need to be improved and
enhanced. The T2L2 (Time transfer by laser link) experiment under development
at OCA and CNES to be launched in 2008 on Jason-2, allows the synchronization
of remote clocks on Earth. It is based on the propagation of light pulses in
space which is better controlled than the radio waves propagation. In this
paper, characteristics are presented for both common view and non-common view
T2L2 comparisons of clocks between China and France.
