And that's without the expenses, extra healthcare coverage, insurance etc.
So pretty average when you considering that junior developer salaries are within this reach in EU capitals.
Junior developers make 75.000€ after taxes? They make about 50 - 60.000€ BEFORE taxes.
I used 4 weeks, and by my experience that's generous (not talking about paid leave - all the freelancers I know are workaholics and don't take much leave, but maybe that's a US thing).
5*48 = 240 days, which works out to around 84000 EUR. Or 120,000 EUR - 30%.
Regardless, 700 EUR/day seems in the ball-park for a generic all-around developer.
£500/day is the absolute minimum for developer/DevOps outside London, £600/day much more common and including the cheap end for London. Senior is more often £800/day. You don't see values above that advertised, but people do obviously negotiate higher for specialist work; I have seen a mainframe developer charging £1500/day (on the low end of his range). Anything higher than that has always been a large consultancy rather than a freelancer. In my specialist niche I'd be asking for £1500/day top-end, expecting £800-1200 with negotiation depending on flexibility.