Requires a free Messe Atlas account (sign in when prompted). The halls and rooms of one venue (slug or uuid from search_venues): kind, level, area m², width, length, clear height, floor load, column-free, capacities (theatre, classroom, banquet, cocktail, 3×3 booths), doors, utilities, notes, and each row's source_url and as_of (stale when older than 180 days). A null figure is not published by the venue. Drawings are not served; geometry_status says whether Atlas holds an outline.