How do I turn off Alarm, Clio MkIII - help??

[shel_65]

I've just bought a Clio MkIII 1.4 16v Privillege. It has what appears to be a factory fitted alarm (thacham 1?). It works on internal movement sensors and neither the garage I bought it from or a local renault dealers can tell me how I turn it off. I might want to do this if I leave my dog in the car while shopping.
All the dealership suggested was sticking masking tape over the sensors and they said it might not be possible to turn it off. Is this correct?

Help please...