From Mr. Jean-Louis Jaraignon I got a nice image of a postcard of the PARIS as depict on the Niger stamp. The image of the postcard is exact the same as the vessel depict on the stamp, so we can be sure she is the vessel. The following information I got from him, and from Mr. Ian L Buxton.
The iron steamship was built in 1856 under yard No.18 by Charles Mitchell at New Castle, U.K. for Schuller Bros, Havre.
23 February 1856 launched under the name PARIS.
April 1856 delivered.
Tonnage 413 gross, dim. 59.35 x 7.3m.
Steam engine 80 hp.
Used together with a sistership the HAMBOURG?, in a service between Le Havre and Hamburg for Compagnie Générale Maritime. ( Schuller Bros?)
1861 Transferred to Compagnie Générale Transatlantique.
Until 1864 in use in this service, her fate till so far unknown.
Niger 1984 80f sg989, scott?
http://www.miramarshipindex.org.nz