Classic fare war happening in Miami today with a good example ticket price of $448 for Miami to Paris on Air Canada, $449 on Air France and $449 on American in March 2017. Cities across France, Italy, Portugal, Spain, Switzerland and assorted other airports are priced in $400s or low $500s through May 2017. For the most part it looks like national airlines are matching any low price from competitors to maintain best fares.
Prices found through Momondo.com were in $460s for Miami to Venice flying late May with Iberia or British Airways, up to $100 lower than actual ticket prices I found for Air France/KLM/Alitalia SkyTeam airlines on Google Flights for Venice in May. Google Flights shows fares as low as $392 with Air France, but those are pricing $564 now on KLM website.
Still there are plenty of real deals easily found through Google Flights from Miami to Europe with a choice of Alliance airlines. Once you find dates and fares you like, see if Momondo.com or SkyScanner.com turns up a lower ticket price with an online travel agency site.
Belgium, Denmark, Finland, France, Italy, Portugal, Spain, Sweden, Switzerland
Paris $472 May 21-30 Air France (several cities across France on sale)
Barcelona, Spain $444 American (several cities across Spain on sale)
Madrid, Spain $445 May 21-30 Air Europa (Skyteam) or Iberia (oneworld)
Porto, Portugal $462 May 21-30 Iberia
Stockholm, Sweden $474 American; $485 SAS (Star Alliance)
Marseille, France $479 American (attack on SkyTeam Air France)
Lyon, France $482 Iberia (Attack on Air France)
Helsinki, Finland $485 SAS (attack on oneworld airline Finnair)
Copenhagen, Denmark $517 Finnair (attack on Star Alliance SAS)
Lisbon, Portugal $535 Air Europa; $549 Air France
Zurich, Switzerland $511 Swiss
Geneva, Switzerland $517 United
Venice, Italy $521 United; $531 Iberia
