Children go to France with chaperone who turns out to be cross-dressed thief. Read in 1990s.

[Sarah]

Read it in the UK in the 90s. Children's book about friends/siblings who go to France with their guinea pig and a chaperone who turns out to be a cross-dressing (art?) thief. One line I remember after the big reveal is that they plan to "tap him on ze nose and serve him with garlic" (the guinea pig).

[Becca]

The guinea pig thing makes me think of Dick King Smith - they feature in a few of his books - but I haven't been able to find one that matches. Was the guinea pig a big part of the story? Do you think they were in Paris?

[Rainbowheart]

The cross-dressing thief sounds so familiar to me, but I can't place it. :/

[Sarah]

The guinea pig was more of a minor character I think. I don't think it was a Dick King Smith, although I definitely read a lot of his books when I was younger.

[Len]

Could it be The Mona Lisa Mystery by Pat Hutchins. The plot involves a school trip to Paris and a supply teacher who turns out to be a thief involved in a plot to steal the Mona Lisa.

[Kris]

Google Books preview of The Mona Lisa Mystery by Pat Hutchins - Len's suggestion:

- https://books.google.com/books?id=PRE...
- There are different cover images.

[Sarah]

Thank you for your suggestion, Len and Kris! I had a look and I don't think it's this one. As I recall, it wasn't a school group but a smaller group of children (possibly related, or a small group of friends like the Famous Five - some older and some younger).