She might get a few Melanchon votes, but I think most of those not voting for Macron will probably just abstain.  She stated that, in addition to Fillon voters, she was after the 4.7% who voted for Nicolas Dupont-Aignan, another centre-rightist.

She hasn't neglected traditional voters who sided with her father, either - that's why she came out only two weeks ago claiming the real France wasn't responsible for the 1942 'roundup' of jews into the Vel d'hiv on their way to Nazi death camps.