The Musée National d'art Modern (MNAM - National Museum of Modern Art) was just one facet of the centre. Known as Beaubourg because of the neighbourhood it is located in, the other elements are the Public Information Library and the IRCAM musical research centre, plus a cinema. The centre was unprecedented because it didn't have to answer to the culture ministry. But revolutions like this one are hard to keep up.
Laurent Fleury, a sociologist at the Université de Paris VII who publishes a history of the Pompidou next month, says the centre achieved a 'democratisation of culture' in France. It changed the way art institutions are viewed and run, and broke the stranglehold of civil servants on cultural decision-making.
In 1971 France's then-president Georges Pompidou launched the project. At that time a lengthy procedure was required for a museum to buy an artwork, and the government's museum authority, the Direction des Musées de France (DMF), had the final say.
'Georges Pompidou was an art lover and he saw how slow the process was,' says Fleury. 'He wanted to make it independent. So at the start, the museum was very independent.'
That was the first revolution - a French president taking a direct hand in cultural policy. It started a tradition of pet cultural projects for leaders of the republic: François Mitterand's Grand Louvre scheme gave that museum its landmark pyramid, and last summer Jacques Chirac left his mark on Paris with the opening of the Musée du Quai Branly, the non-western art museum in Paris.
The second revolution, Fleury argues, was the centre's influence on the country's cultural scene. The so-called 'Beaubourg effect' went deep.
'The model was much imitated,' says Jean-Michel Tobelem, an arts management specialist who runs the Paris-based research institute Option Culture. The centre was the first to introduce a membership card for unlimited access to all shows - a system later followed by its competitors such as the Louvre and the Musée d'Orsay. The Louvre and others also followed the MNAM's example by gaining control of their budgets from the government.
'At the start, and for at least 15 years, it was not only an unusual institution, but quite revolutionary,' says Claude Fourteau, who worked at the centre from its beginning until 1994. She was responsible for the then-novel duty of helping the museum reach out to the public.
'The core principles were a multidisciplinary approach, openness and a truly new relationship with the public,' she says. 'It was 1977. Picasso was a name people were still afraid of. But the MNAM made people feel at home. That's Beaubourg's great success.'
This multidisciplinary approach made the centre unique, but also tough to manage, adds Fourteau, who went on to work for the Louvre before becoming a freelance museum outreach consultant.
'Today, the MNAM is a classic museum, whereas in the beginning it was very original,' says Fleury. 'In the beginning there was the idea of "moving walls", then around 1986, the walls became fixed. That is the polar opposite of the initial plan for the centre, which was fluidity, free movement and a multidisciplinary approach.'
The next watershed was a relaunch of the centre in 2000 after a three-year renovation. The museum said the work was needed since unexpectedly high visitor numbers had put a strain on the modern materials used to realise Richard Rogers' and Renzo Piano's outlandish design.
'It had become a bit of a forum, a bit tramp-ridden on the ground floor, which was open to everyone. The best way to handle the problem was to control the entrance,' says Fourteau.
The changes introduced with the reopening were a blow to the centre's inclusive ideals: a charge to access the upper floors where most shows and collections are displayed and the use of separate entrances to the library and the museum effectively split the centre.
The challenges have not let up. At the time of the centre's inauguration, most staff were in their 30s. Three decades on, many of them are still there and have reached retirement age, so a race has developed for the older staff to pass on their expertise.
'The teams that founded the museum are ready to retire,' says Didier Ottinger, the head of the MNAM's early 20th-century painting and sculpture collection. 'There has been a big renewal of personnel over the past ten years. Now we're calling on young curators, people at the start of their careers, and curators who are not necessarily French,' he says. He has taken on staff from Germany and Poland to help broaden the museum's expertise in different areas of modern art.
The centre is also developing further afield. Last November, workers broke ground on the site of a new Pompidou Centre in the north-eastern French town of Metz. 'We have a problem of space in the museum,' where 1,300 works will be on display this year from a total of 58,000 items in the collection, says Ottinger. He says the collection is continuously expanding, so they take every opportunity to increase the space.
Last year, the centre also began investigating the possibility of opening a branch in Shanghai, reflecting the interest of various museums in the emerging Asian market.
Meanwhile, with the new outposts, observers say the Beaubourg institution will compromise one of its main strengths: it will cease to be the one and only Pompidou Centre. But Fleury stresses that there has always been more to Beaubourg than exhibition space.
'The library gets most of the visitors, and IRCAM is the top musical research laboratory in the world - but all that has been overshadowed. Why has Beaubourg become regarded as a museum, when it was supposed to be something quite innovative?' he asks. 'I don't think we have the right to consider it only as a museum.'
The Pompidou Centre - and the art museum that has become its popular face - has already achieved its mission of bringing the arts to a wider public, says Fourteau, despite the compromises involved in the 2000 overhaul. But the latest annexe projects would not have been dreamt of at the time of Beaubourg's inauguration.
The anniversary year will be marked by a two-stage rehang in the museum: this month sees the unveiling of the modern collection, reorganised with works by major names such as Matisse and Giacometti tying in with exhibits of photography, architecture and design, plus a selection of documents from the museum's arts archive, the Bibliothèque Kandinsky.
In April, the contemporary collections will be presented in a rehang linked to Airs de Paris, a temporary show on urban themes, accompanied by performances and debates.
'Our big challenge is that of all modern art museums - how to write the history of modern art,' says Ottinger. 'That's why we're being so experimental.'
Competing in a cultural landscape that it revolutionised, Beaubourg must now fight hard to stay unique.
Roland Lloyd Parry is a freelance journalist based in Paris