Compulsory bike accessories you need
To meet technical operating conditions for bicycles in road traffic, they must be equipped with:

a) An easy-to-use, reliable steering device that doesn’t hinder other controls.
b) Two independent brake systems effective in all weather conditions.
c) A sound signalling device, typically a bell.
d) A front lamp emitting white or cadmium yellow light visible from 150 meters in clear weather.
e) A rear position indicator emitting a red light from 150 meters in the dark.
f) One white reflector is at the front, and one or two red reflectors are at the rear, symmetrically placed.
g) At least two amber-coloured side reflectors on the first wheel, effective on both sides. Alternatively, a white reflective ring surface can be used near the rims or on the tyres.
Source: Police.hu