Can I transit in Zurich, Switzerland, on my way back to South Africa with an emergency passport issued by the South African consulate in Paris? Do I need a transit visa for this flight with the emergency passport?
That's what an emergency passport is - a passport. It's meant to be traveled with.
As to transiting through an airport, that usually doesn't require a passport, since you're not technically entering the country. But in this case especially if you're coming from Paris and so already in the Schengen area.