Siddalls said It sounds as if Gilly is a French resident, and as such, she would be liable to French taxation on her worldwide income and assets, even if "offshore".
For its relatively new brand Gilly Hicks that sells intimate wear for teen and young women, sales have been improving considerably, but it still constitutes a very small portion of total sales (around 1%).
Gilly should also be aware that if she leaves her money offshore French social taxes also apply at 11% on any investment income such as bank interest, as there is no 'nil' band for social taxes for French residents.