(9 yrs ago)
Per their website, HK/China contact/retailer:
Unit 1303, East Ocean Center, Granville Rd, TST.
Tel 00 852 27070022
There is supposedly a salon/shop in Harbour City mall, TST, shop 225 (2nd floor),if it is still operating there.
You can order some Guinot items from Strawberrynet (based in HK and free delivery). It now has its website for HK in English, instead of just Chinese.