A council has warned residents not to attach objects to trees - in a notice attached to a tree.
Islington Council said the poster in Highbury Fields, north London, had been put up "in error" by a junior worker.
It read: "Please do not attach or affix any structures or objects to the park furniture and trees at Highbury Fields including the benches and lamp posts."
A council spokesman said it had now moved the notice to a nearby noticeboard.
The notice, which asked residents to respect the park and be responsible, was spotted by Nadi Jahangiri, an architect who lives nearby.
He said: "A lot of people have been putting signs up on the trees about lost cats and so on with drawing pins - it really annoys me.
"I walked up to it to rip it down, only to find it was telling people not to attach anything to trees!"
He continued: "Lots of people soon gathered around laughing.
"There was lots of grumpy huffiness and indignation about our taxes being used for this.
"If you want to stop someone doing something, doing it yourself is an odd way to go about it - but that's Islington Council for you."
A spokesman for the council said: "This was a mistake by a junior member of staff who thought they were doing the right thing to protect the trees.
"Yesterday we removed the sign to a nearby noticeboard as intended."