Ms Mushikiwabo, Rwandan Minister of Foreign Affairs, was appointed Secretary General by consensus at a closed meeting on the last day of the Yerevan Summit of the International Organization of La Francophonie (OIF), a kind of mini-UN 84 states and governments.
Her appointment was not longer in doubt after her rival, Canadian outgoing Michaëlle Jean, lost his two most important supporters: Canada and Quebec.
These two pillars of the French-speaking world, which are, between them, the second largest donor, have been forced to give up in view of the growing number of countries rallying behind Rwanda.
For some African commentators, the decision is a stitchup between French President Emmanuel Macron and Rwandan President Paul Kagame that does little for France's reputation or the OIF's mission.
"The silence is deafening," said Mathias Hounkpe of OSIWA, the West African branch of the Open Society network of thinktanks, describing how African countries have responded.
Other voices harshly recall France's history of back-door dealings in former sub-Saharan colonies, often at the expense of human rights and democracy.
"It's like Francafrique," said Ivory Coast commentator and author Alex Kipre, referring to a notorious policy of interference that Paris insists was ditched years ago.
Created in 1970 along lines blazed by the Commonwealth, the OIF brings together 58 countries and regional governments, representing 274 million speakers of French around the world.
Just months ago, the big name expected to be adopted in Erevan was the current OIF secretary general, Michaelle Jean -- a Canadian of Haitian descent who in 2014 became the first woman and non-African to helm the organisation.
But her fortunes changed in May when Kagame visited Paris.
After talks with Macron, he announced -- in English -- that his foreign minister would be seeking the leadership of the world's francophone community.
Macron declared his support, saying Mushikiwabo had "every quality for the job".