French minimum wage of 1,521.22 Euro PCM (divided by France's 35 hour week * 4) = 14.48 Euro per hour / $15.98
This also doesn't take into account things like top-up tax credits for low earners, access to social housing, free childcare and a zero up-front cost on healthcare. So take home wage is substantially higher than the hourly rate would indicate.
There are actually 4.43 weeks in a month. The shorter French work week also hurts here. Over a third of minimum wage workers in the US work full time, which makes their monthly salary about $1,950 per month, or 1,765 Euro per month. (15% higher than French minimum wage.) There is serious debate in France about getting rid of the 35 hour work week: https://www.france24.com/en/20170413-french-presidential-can....
Also, the US has a substantial tax credit for low earners (EITC). But that’s a bit far afield from the point OP was making, which is that working people shouldn’t have to draw on public welfare benefits. European minimum wages are low enough where companies are still “subsidized” by benefits paid to low income workers.