The military has been keeping a close watch on former prime minister Yingluck Shinawatra since she flew to Paris where she will attend her self-exiled brother's birthday party on Saturday.
A photo posted on Instagram by @ingshin21, supposedly Paethongthan, Thaksin's youngest daughter, on Friday.
A Royal Thai Army source told the Bangkok Post her every move was being monitored and pictures of her taken while she is in France.
The National Council for Peace and Order will also do the same when she goes to England and Los Angeles later, the source said.
"We asked Ms Yingluck not to meet any political group and join a meeting which may have political significance. We asked her to keep it among family members," he said.
This might have explained why her former prime minister brother Thaksin Shinawatra kept his birthday party a private affair this year. In any case, a few Pheu Thai party executives close to the family may join it.