The most outspoken of proponent of Frexit in France is Marine Le Pen, sometime leader of the Front National (FN) party (a position renounced as she campaigned for the presidency). Most people saw a presidential win for Le Pen in the 2017 French election as the most likely path to Frexit, as her election rival Emmanuel Macron was stridently pro-EU.
After Le Pen lost the second round of the election to Macron, the probability of Frexit in the next few years dropped to near-zero. Whether it flares up again will depend on how Le Pen decides to try and build on her first round success - where she took 21.5% of the vote, more than the candidates from either of the two mainstream parties - and where the FN party goes from here.
But problems still exist. A 2016 poll found that 61% of France had an unfavourable view of the EU (compared to 48% in the UK), which appears to indicate that while the French public might not have wanted Le Pen in office, many do have real reservations about the union.