Not just that.

Upon Googling "can cats eat lemon":

The answer is a firm no. Lemons and other citrus fruits can harm your feline friend because they contain toxic compounds that are poisonous to most domestic pets. These toxins are present not only in lemon fruits but also in lemon trees, so pet owners who are also lemon tree gardeners should exercise caution.

( Source: https://minnetonkaorchards.com/can-cats-eat-lemons/ )

I just copied the first example, but the results page is full of warnings. One claimed it's fine for a cat to lick them, but I wouldn't want to expose a cat to lemon anyways. Not as food, or toy, or headwear.