You can transport children in child seats, as stated in the Road Traffic Act. 

Almost all SPARK cars, except for the Nissan Cargo eNV-200 models, are equipped with a booster seat for children between 15 and 35 kg. You will find it in the trunk of the car or in the back seat. 

All electric cars have an ISOFIX base, so you can install your personal child seat. This is a convenient option, especially for longer trips and outside-the-city trips.