Tacitus, AE silvered Antoninianus. Lyons.

IMP CM CL TACITVS PF AVG, radiate, draped, cuirassed bust right
PAX AETERNA, Pax standing left, holding olive branch and 
sceptre.
Left field: B.
Right field: Star.

RIC V (1) 33; Estiot 1237, Bastien 97, La Venera 1796

Sold on ebay in March 2010 by French seller Philippe Lacoste.