I believe "quiet hours" in the summer (from April 1st) are designated between 11 p.m. to 7 a.m. and 3 to 5.30 p.m. Residents are allowed to make a complaint to the police if disturbances are noted between these hours and during the customary siesta break.
This means that between those hours, residents are not allowed to carry out construction or other activities that cause noise, practice musical instruments or play music at high volumes, carry out noisy discussions or arguments, or use alarms or other security systems without due cause.
I recall this subject was raised on "The Forum" 2-3 years ago. There are slightly different hours for winter.