Mine broke off and ended up in the engine but did no noticeable damage in several thousands of miles of driving. I think the new one cost about £9 from a Citroen dealer (who had 10 in stock, must be a common occurence!). I would not worry about it.
I notice that the dipstick on my new L2 90hp HDi now has a metal rod between the handle and the tip, instead of the plastic rod previously fitted (and prone to snapping!).