Literal translation
to walk on sea urchins
Meaning
to be in a situation calling for great caution
Explanation
This expression means to be in a situation calling for great caution, where the slightest careless move can have painful or unfortunate consequences. The sea urchin, a marine animal covered in sharp spines and very common along the rocky Provençal coast, cruelly wounds anyone who accidentally steps on it: walking on sea urchins, or rather treading, frolicking over them as the verb trepa suggests, thus demands constant vigilance with every step, on pain of immediate pain. Applied to a social, professional, or family situation, the image describes a delicate context where every word or decision must be weighed with the utmost care, exactly as ordinary French says walking on eggshells, to which this Provençal phrase corresponds term for term in meaning, though with a local image rooted in coastal reality. The register is familiar, used to describe or anticipate a negotiation, a conversation, or a tense context where clumsiness is not tolerated. The expression illustrates the Provençal preference for drawing comparisons from the immediate environment, here the rocky shore and its characteristic wildlife, concrete and vivid.