You cannot claim a diploma for the preparatory classes you have taken. However, your preparatory classes are equivalent to 120 ECTS-compatible credits (European Credit Transfer and Accumulation System) and give you direct access to the 3rd year of a Bachelor's degree and the opportunity to obtain a Bachelor's degree.
To be eligible, you must hold a recognised 3-year university degree or equivalent, accredited to a minimum of 180 ECTS credits. You must therefore indicate in your application form, in the 'type of diploma' field 'Licence/Bachelor, in the 'length of study programme' field a minimum of 3 years and include your preparatory years in the start and end dates of the study programme. In the 'comments' section, you can specify that your degree was obtained due to your preparatory years.