This is not my discovery. There already was lots of discussion about this:
The logo might be an allusion to Matisse's danse although the designers deny it. In some cases how you deal with a pictorial quotation makes the difference between allusion and plagiarism. The question is how designers even with an average arts education could not feel reminded to Matisse's painting at least after they had created the logo. Nevertheless there remains the possibility that the creators of the logo didn't know Matisse's danse.

Awesome image.

This is an example for an honest "allusion":

Source: www.b3ta.com/board/11017551

Matisse - La Danse des Saucisses
From the Sausage Art challenge. (One out of 167 entries): www.b3ta.com/challenge/sausage-art/popular
Artist: monkeon schmonkeon www.monkeon.co.uk, Sat 5 Oct 2013, 16:15

It seems to echo Matisse too directly, without tapping into the rich Brazilian traditions of dance. It just feels derivative, lazy and unimaginative. It probably suits the corporate behemoth the Olympics has become.

Yes, it looks like a quite direct re-use of Matisse's painting. Whether plagiarism or not, I too don't like the logo.

" [...] Rio, on the other hand, seems to have gone too far in the other direction. If London is all bared teeth, Rio rolls over and wants us to tickle its tummy. Each organising committee requirement is present and correct: happy amorphous dancing people of the type seen in so many logos before (and, yes, as also seen in Matisse), soft edges where London is jagged and city landmark front and centre (though, I admit, I wouldn't have recognised the Sugarloaf unprompted). [...]"
Source: Rio 2016 Olympics logo: a closer look, by Patrick Burgoyne, 4 January 2011, 21:11
www.creativereview.co.uk/cr-blog/2011/january/rio-2016-logo-longer-look

- Henri Matisse (1909): Integration into a still life, www.google.com/search?q=dance+matisse+still-life+1909&tbm=isch
- George Segal (1971-1973): The Dancers, www.google.com/search?q=%22George+Segal%22+%22The+Dancers%22&tbm=isch
- Roy Lichtenstein (1974): The Dance, href="www.google.com/search?q=lichtenstein+dance+matisse&tbm=isch

See also p. 108-109 in Art about Art (1978) by Jean Lipman and Richard Marshall