The boxes are barely open when the first bites appear, clustered around the ankles and lower legs. You have no pet, the flat stood empty for several weeks between tenancies, and yet the verdict is clear: fleas. It is one of the most common calls we get in early autumn, when many leases change hands.
The phenomenon makes perfect sense once you know the insect's life cycle.
The empty-flat trap
The species we meet in the vast majority of cases is the cat flea (Ctenocephalides felis), which lives on dogs as readily as on cats. The adult is 2 to 3 mm long, brown, flattened sideways, and jumps a very long way for its size.
The adult flea lives on the animal, but its eggs do not stay in the fur: they drop to the floor, into rugs, between floorboards, into the corners of the sofa. A commonly quoted breakdown surprises people: in an infestation, adults make up only about 5% of the population. The rest is eggs, larvae and cocoons, all invisible, spread around the home.
The cocoon, a waiting room
The larva eventually spins a sticky cocoon disguised with dust. Inside it, the flea can stay dormant for several weeks, even several months, if nothing happens. It waits for specific signals:
- vibrations (footsteps, a removal trolley);
- warmth;
- carbon dioxide, the kind we breathe out.
When the previous occupant leaves with their cat, the silent flat stays "on standby". The day you arrive, with all the coming and going and the boxes, dozens of hungry adults emerge at once. And the only host available is you.
Confirm that it really is fleas
Before treating, you need to be sure of the insect. Two simple tests:
- The white sock test: pull on long white socks and walk slowly over rugs and floors for a few minutes. The dark fleas show up clearly on the fabric.
- The light trap: in the evening, put a plate of slightly soapy water on the floor under a lamp that is switched on. Fleas drawn by the warmth and light fall into the water.
Flea bites are usually small, very itchy and clustered on the ankles and calves. That pattern often sets them apart from bed bug bites, which tend to be on the upper body and skin left uncovered during sleep. If in doubt, keep an insect on sticky tape for identification.
The four-step action plan
1. Vacuum every day, really every day
The vacuum cleaner is your best ally. It removes eggs and larvae, and its vibrations push adults out of their cocoons, exposing them to the treatment. Go along skirting boards, under furniture, into floorboard gaps and over the sofa. Empty the container or throw the bag away in a sealed bag outdoors after each session.
2. Wash whatever can be washed
Sheets, throws, removable cushion covers, washable rugs: machine wash at 60 °C, then dry. Delicate fabrics can be treated with a steam cleaner.
3. Treat the home, not just the visible insects
The knock-down sprays sold in shops only hit the adults present at the moment you spray. A professional treatment combines a suitable insecticide with an insect growth regulator, which stops larvae from becoming adults. That is what breaks the cycle. The home has to be vacated for a few hours, and you then follow the technician's instructions: usually you keep vacuuming but avoid washing floors with water for several days.
4. Do not forget the pets
If you are moving in with a dog or cat, have it treated with an antiparasitic product prescribed or recommended by your vet, on the same day as the home. Otherwise the animal reinfests the place.
| Step | Who | When |
|---|---|---|
| Daily vacuuming | You | From day one, for 2 to 3 weeks |
| Washing fabrics at 60 °C | You | Before the treatment |
| Insecticide + growth regulator treatment | Technician | One visit, follow-up depending on the situation |
| Pet antiparasitic | Vet | On the day the home is treated |
Tenants in France: what the law says
Since the ELAN law of 2018, article 6 of the French law of 6 July 1989 states that a landlord must hand over a decent home, free of any infestation by pests and parasites. If fleas show up as soon as you move in, that is a strong argument.
Our practical advice:
- tell the landlord or letting agency in writing, quickly, giving the exact date the bites started;
- attach photos of captured insects and of the bites;
- keep your check-in inventory and every invoice related to the problem.
The photo report our technicians send on the day of the visit can also serve as evidence in these exchanges.
Calling DeratiseurPRO
We handle flea infestations across the whole Île-de-France region as part of our insect treatment service. To learn everything about the insect, read our flea guide. Prices are shown on the pricing page and you can book your slot online.
FAQ
Your questions
How long can fleas survive in an empty flat?
Adults die fairly quickly without a host, but fleas still inside their cocoons can wait several weeks, even several months, before emerging. That is why a home left empty between tenancies can cause bites as soon as the new occupants arrive.
Can you get fleas without having a pet?
Yes. Eggs and cocoons left behind by a previous occupant's pet are enough, as are those brought in by rodents or by an animal passing through a cellar or garden. With no usual host, adult fleas then bite humans, especially around the ankles.
Who pays for flea treatment in France: the tenant or the landlord?
If the infestation existed before you moved in, the landlord is required to provide a home free of pests and parasites, which argues for the landlord paying. If it appears later, for example because of the tenant's pet, it is in principle up to the tenant to act. Either way, notify in writing and keep dated evidence.
