can all the people in the world fit into france?

Yes start with Chinese, stack them 3 high, then put India on top 2.5 high, Africa and Middle East 1.5 then one high each of SouthAmerica, North America, s.e. Asia, Europe, Russia,  and last Australia with .25 persons. There will however be a problem with toilets.

Yes...absolutely. The population density would be fairly high...the country would be filled with what would look like mostly 'CITY' or urban population with lots of high rises etc. Our current urban centers are really not that space efficient, we could easily increase density levels.

No way, France is only a country, the entire world population cannot even fit into any continent.

The entire population of the Earth could fit onto the Australian  island State of Tasmania with about 9 square metres per person. France, which is almost ten times the size of Tasmania would have 86 square metres per person (presuming a world population of 7.5 billion).

Easily but not very comfortably. 

It is Somethig like 90 people in a square kilometre

Back in the late 60's the whole of the world's population could fit on the Isle of Wight - but it's grown since then!

Could still fit easily into France though

I will give you the answer, but you first have to choose my answer as best then I will comment and put the full answer in. I am your only hope seeing that no one else answered your questions