actually u can DIY french manicure. You just need base coat, top coat, white polish and tape(the a little yellowish type).
1. apply base coat and let it dry
2.cut the tape in some crescent shape, stick it on all 10 fingers, leaving a mere 1.5mm on ths tips on you finger.
3.paint white polish on the 1.5mm tips and let it dry
4. peel off the tape
5.apply top coat and you get a french manicure

tips: pactice make perfect. It is also good if you know to shape you finger so that it looks profesionally done