Paris is one of the most consistently cheap destinations in Europe recently. Spring 2018 travel from San Francisco to Paris is pricing at $350 round trip tickets flying United and other Star Alliance airlines for April and May 2018 departures.
Google Flights shows $440 fare dates. Search low fare dates on Google Flights and then plug those dates into Momondo.com. Chances are a ticket price near $350 is offered through an online travel agency.
Google Flights United operated flights on LH ticket
$440 round trip Mon April 23 – Sat May 5
Momondo.com search and TravelMerry.com ticket
Air Canada outbound SFO – Montreal YUL – Paris CDG
United Airlines inbound Paris CDG – Chicago ORD – SFO
$348.56 round trip Mon April 23 – Sat May 5
Momondo.com search and TravelMerry.com ticket
United Airlines SFO – Chicago ORD – Paris CDG (Ord-Paris LH codeshare) – Paris CDG – SFO (UA nonstop).
$354 round trip Sat May 5 – Sat May 12
