Selling French shares advice?

[DingbatsFur]

Hi,
My mother has some French shares after living there for some time. She now lives in North America. She would like to sell the shares, however the bank she has them with has advised she can only sell them if she or someone who has power of attorney instructs them in person to sell the shares.
Despite being a fluent french speaker she is baffled by their vocabulary being used here.
She was advised to sell half in one calendar year and the other in the next calendar year and so avoid the French capital gains tax, but this would mean she would have to go there in person twice.
There is no family left in France who can assist.
Any ideas? The French bank is very unreasonable.