CHINA. (FRENCH POST OFFICE IN SHANGHAI). 1873. Envelope showing 'Nachtrieb, Leroy & Co,' firms chop in blue addressed to France bearing 'French Republic' Yvert 57, 80c rose and Yvert 60, 20c blue tied by '5104' in lozenge with Shang-Hai Chine double ring '5th Avril 75' on face, boxed 'PD' and endorsed 'via Marseille' with Lyon arrival on reverse '17th Mai'. Very fine