Bélanger is described by the Penguin dictionary of architecture as the 'most elegant Louis XVI architect' whose 'masterpiece [is] the exquisite neo-classical Bagatelle in the Bois de Boulogne, Paris' designed and built in 1777. His scheme for a gallery at Lansdowne house, 1779, conforms with the plan by Robert Adam published in The Works in architecture of Robert and James Adam, volume II, 1779, part III, plate I, with a space about 103 feet long and 29 feet wide, divided into a larger central area with two octagonal rooms at each end. This tripartite arrangement is emphasised by two screens in the form of a Palladian motif that as Stillman (1970, p.79) points out was 'a theme whose popularity in France came substantially later than in England, where it had been virtually endemic since about 1715. A number of other motifs seen here are also reminiscent of English Neoclassicism, but their character and the way they are used are not at all English... the spirit and the context are quite different from those of Adam or his English contemporaries. Here we see areas that are more crowded and filled in, though characterised at the same time by an increased refinement that is essentially French.'

Bélanger's gallery design went unexecuted and in 1786 a design for a library was commissioned from Joseph Bonomi (RIBA Drawings Collection C₃[15]No.2) that was then superseded by Dance's executed scheme for a library.

LITERATURE. D. Stillman, 'The Gallery for Lansdowne House', Art Bulletin, LII, 1970, pp.75-80.