Here is a link to a wikipedia article covering polling over the past few years in he french presidential race.

https://en.wikipedia.org/wiki/Opinion_polling_for_the_French_presidential_election,_2017

Au contraire to Mr Yakabuski's opinion that Le Pen is gaining, the figures show Le Pen's  support at worst  dropping from the low 30% levels of 2015 and part of 2016 and at best holding even just above 25% first round. Fillion is down, now firmly in 5rd place, and Macron is moving up, as centre left and green voters seem to be moving to Macron , as Fillion is to catholic cnservative on moral issues and too Thatcherite on economic ones , and those former working class voters who used to vote left but now like Le Pen have already gone to Le Pen. 
And those supporting Harmon the more  leftwing Socialist candidate, should be more willing to vote Macron to stop too right wing candidates. 

Anything may happen,but The establishment centre-right made a real mistake rejecting Juppe for Fillion.