I don't know what 1/5 of France's electorate feels about anyone - I only know that, of those that voted, that is how many voted her.
Macron - 23.9%
Le Pen - 21.4%
Fillon - 19.9%
Melenchon - 19.6%
Others - about 12% in total
So, yes, more than one fifth of the voting electorate put her in the run-off.  Judge that as you choose.
Now you know.