SkyTeam airlines Air France / KLM and their partners offer very reasonably priced flights to Paraguay, usually very expensive destination in South America. You can fly either from France (Paris, Lyon, Marseille, Toulouse) or Amsterdam to Asunción, capital and the largest city of Paraguay. Round-trip tickets are now starting at €483 including all taxes and fees when departing from France. Flights from The Netherlands are a bit more expensive now from €515. You can also putchase tickets with much more convenient routing. (one short layover in Sao Paulo, Brazil). 
This KLM / Air France promotional deal is valid for bookings made till 23rd of November 2016. The cheapest flights are available between March and June 2017. (From France look for the flights departing from April 2017 and onward). Max stay 1 month.
Booking samples
Amsterdam - Paraguay for €529 (directly with the carrier)
Amsterdam - Paraguay from €515 (with two layovers or for €546 with one layover)
France - Paraguay for €502 (directly with KLM)
Need hotel room in Paraguay we recommend Booking.com To further discount your accommodation you may consider promotion codes offred by Venere, Hotelopia, Hotels.com or Amoma.
Booking sample of these cheap Air France / KLM Return flights from Amsterdam or France to Paraguay from €483 here. In this case you would depart from Lyon to Asuncion on 27th of April 2017. Your return flight from South America back to Europe would be on 13th of May 2017.
