The Organisation for Economic Cooperation and Development, derided as a "rich nations' club" that vegetated in its Parisian chateau for decades, has redefined itself as the go-to resource for economic analysis.
"When I started my career (at the French finance ministry) in 1996, they sent me to visit the OECD. I said to myself, 'God, I hope I don't end up here!'" said Pascal Saint-Amans, recalling his impression of the institution as "second tier".
But Saint-Amans, a graduate of France's top administration school, did indeed wind up at the think-tank, joining in 2007 after the group had, in his words, "taken off".
Today he heads one of the body's biggest units, the crime-busting Centre for Tax Policy and Administration.
Many attribute the turnaround to Angel Gurria, who took over as OECD secretary general in 2005.
The worldly Mexican economist has just embarked on his third six-year mandate after the OECD's 34 member states unanimously re-elected him last week.
He plays host Tuesday and Wednesday to the OECD Forum, an annual get-together with an A-list of guests who will include French President Francois Hollande.
When Gurria took the helm, the OECD was a stodgy consultative body, an outgrowth of the Marshall Plan for the reconstruction of Europe after World War II and strongly associated with the Western side of the Iron Curtain.
Gurria, Mexico's finance minister from 1998 to 2000, had made a name for himself by ably renegotiating his country's debt with support from Washington, by far the biggest financial contributor to the OECD.
A decade later, he joined in with the ministers of the Group of 20 leading economies to tackle the 2008 financial crisis.
Jovial, multi-lingual and tenacious, Gurria has criss-crossed the world, toting all manner of reports -- evaluations of national school systems known as PISAs, studies on binge drinking among young people, black lists of tax havens, analyses of income inequality, economic growth forecasts...
- 'We are a do-tank' -
"Today the OECD is more relevant and has a greater impact, perhaps because we have better identified the subjects that interest our members," Gurria told AFP.
"We are not a think-tank, we are a 'do-tank', which means that the research we do is aimed at public policy-makers, not seminars or political debates," he said.
Governments have become keen consumers of Gurria's recommendations, always delivered with a smile and no obligation.
When things got especially tense in Greece late last summer, its bailout creditors took refuge at the OECD's elegant headquarters in western Paris for their deliberations.
In February, when the radical left Syriza government came to power in Athens, it consulted with the OECD.
Greek Prime Minister Alexis Tsipras said he felt comfortable with the institution, even if it favours business-friendly policies such as a flexible job market, budgetary rigour and competition.
"The organisation has not become a Trotskyist lair," joked Saint-Amans. "The basics remain liberal, but there is an acknowledgement of issues such as tax fairness and inequalities."
The institution, which had a budget of 357 million euros ($389 million) in 2014, has become a virtual recruiting agency for consultants.
It offers lucrative short-term projects such as a stint for an energy policy analyst with three years' experience paid at up to 6,800 euros per month -- tax free.
The OECD, champion of tax fairness, itself enjoys tax-exempt status like other international organisations.
It is not secretive about its salary scale, revealing that it pays its boss a base salary of 200,000 euros.
It has also begun opening up to modest and emerging economies, welcoming the likes of Estonia, Chile, Israel and Slovenia into its membership.
Colombia will join soon, while Brazil, China and India enjoy "enhanced engagement".
But the "world according to the OECD" is not everyone's oyster.
Its Programme for International Student Assessment (PISA) evaluations are controversial, for example. Last year, academics from around the world signed an open letter in the British daily The Guardian saying that the tests are too quantitative and utilitarian.
"We fail to understand how your organisation has become the global arbiter of the means and ends of education around the world," rather than the United Nations or its children's agency UNICEF, they wrote.
The OECD's spearheading of international negotiations against tax fraud and evasion has also been called into question.
"The process is biased" in favour of wealthy countries, said Manon Aubry of Oxfam France. "Developing countries are not involved in the negotiations, and when you are not seated at the table you wind up on the menu."