The caravan depends on car insurance
It is not advisable, or even permitted by insurers, to have separate car insurance for the towed part of the caravan. In general, contracts automatically grant the civil liability cover of the insured car to the caravan when it is towed, free of charge... if its total weight does not exceed 750 kg. For a higher weight, it is advisable to take out additional insurance, which can be combined with optional cover that is also valid when the caravan is uncoupled.
... except when it is uncoupled
When the caravan is uncoupled, it is no longer covered by the car insurance in traction, it must be covered by additional insurance. All the climatic risks, which are increasingly unpredictable, can also occur: hail, gales, falling trees, fire, lightning, sudden rise in water level, etc. In general, these claims are grouped together in the same level of cover, and only the amount of compensation and excesses may vary.
The special case of "natural disasters
Finally, it should be remembered that certain events only give entitlement to compensation after a natural disaster decree has been published in the Journal Officiel. Beware, of course, of the exclusions that appear in contracts. Tents and awnings, for example, are not necessarily covered. The same applies to outdoor furniture. As regards a fire limited to the caravan, if this loss is due to a defective appliance or to the consequences of a burn (cigarette, storage of flammable products, etc.) the guarantee will not work.
Our advice: regular maintenance
The first piece of advice is to have your caravan regularly serviced: after a road accident, an insurance adjuster could attribute some or all of the responsibility to you if it turns out that the vehicle's maintenance, which was not carried out (faulty brakes, etc.), was one of the factors that caused the accident.