"An exhibition is a display which, whatever its title, has as its principal purpose the education of the public: it may exhibit the means at man’s disposal for meeting the needs of civilization, or demonstrate the progress achieved in one or more branches of human endeavour, or show prospects for the future." 

1928 Paris Convention, Article 1


The 1928 Paris Convention, which created the BIE and established the rights and responsibilities of the organisers and participants of an Expo, applies to all international exhibitions held by governments except:

  • Exhibitions lasting less than three weeks
  • Fine arts exhibitions
  • Exhibitions of an essentially commercial nature

The BIE today categorizes these international exhibitions into two main types: World Expos and International/Specialized Expos.

The BIE’s role with respect to these exhibitions is to ensure the just application of the Convention and of other BIE regulations as well as to arbitrate any dispute that may arise between countries competing to host an exhibition or between participants and organizers of an exhibition.

The two types of Expos differ principally in the size of the Expo site, the duration of the event, and the scope of the theme (see chart below).

In regulatory terms, World Expos and International/Specalized Expos are referred to as “International Registered Exhibitions” and “ International Recognized Exhibitions”, respectively.

Since 1931, the year the 1928 Paris Convention came into effect, there have been different modifications to the categorization of Expos. The current categorization, described here, has been in use since 1996, the year the Amendment of 1988 came into effect.



CATEGORY Registered Recognized
FREQUENCY Every 5 years Between 2 World Expos
DURATION 6 months 3 months
PARTICIPATION States, international organizations, civil society, companies States, international organizations, civil society, companies
THEME The theme must reflect a universal concern The theme must be specialized
CONSTRUCTION The participants themselves design and build their own pavilions The pavillion's modules are free of rent and charges and are made avaiable to participants by the organisers
SITE Unlimited surface 25 hectares maximum
HOST CITY City looking to accelerate projects of urban and economic renewal City looking to establish themselves on the international arena and to promote growth

Since 1960, the BIE also grants recognition to the International Horticultural Exhibitions (“A1 International Exhibitions”) approved by the AIPH (International Association of Horticultural Producers).

The BIE also recognizes the Milan Triennial Exhibition of Decorative Arts and Modern Architecture, on the grounds of historical precedence, provided that it retains its original features.