Thanks for tips.
Car's been in garage two days ago. Filters,
and coolant changed except diesel filter.
Tyre pressure is at recommended.
I have sent message to renault techline for their opinion.
Not speed limited as such, but all engines have a rev-limiter to prevent damage.
Possibly the car's needing a service? A dirty air filter will restrict the amount of power produced = a reduction in top speed.
Even factors such as low tyre pressures will have an adverse effect.