Head-up display for a motor vehicle, said head-up display comprising: - a first image-generating unit controlled by a computer for generating first images (Img1), - a second image-generating unit , distinct from the first image-generating unit and controlled by a computer for generating second images (Img2), and - an image-projecting optical assembly , which is configured to concomitantly project the first and second images (Img1, Img2) into the field of view of the driver of the motor vehicle and which comprises a partially reflective mirror, on either side of which are placed the first and second image-generating units , wherein said mirror is a spectrally selective optical filter configured to predominantly reflect light at least at a first wavelength (λ 1 ), and to predominantly transmit light at least at a second wavelength (λ 4 )distinct from said first wavelength (λ 1 ), and wherein: - the first image-generating unit comprises at least one monochromatic light source , which emits only at said first or said second wavelength (λ 1 , λ 4 ), respectively, - the second image-generating unit is configured to generate a light beam in a wavelength band (Δλ) that contains said second or said first wavelength (λ 1 , λ 4 ), respectively, and - said spectrally selective optical filter is configured to transmit or reflect, respectively, light in most of said wavelength band (Δλ), and wherein said first image-generating unit is a laser scanner that comprises at least one laser diode emitting a wavelength (λ 1 , λ 4 ) comprised in the wavelength band (Δλ). - a first image-generating unit controlled by a computer for generating first images (Img1), - a second image-generating unit , distinct from the first image-generating unit and controlled by a computer for generating second images (Img2), and - an image-projecting optical assembly , which is configured to concomitantly project the first and second images (Img1, Img2) into the field of view of the driver of the motor vehicle and which comprises a partially reflective mirror, on either side of which are placed the first and second image-generating units , wherein said mirror is a spectrally selective optical filter configured to predominantly reflect light at least at a first wavelength (λ 1 ), and to predominantly transmit light at least at a second wavelength (λ 4 )distinct from said first wavelength (λ 1 ), and wherein: - the first image-generating unit comprises at least one monochromatic light source , which emits only at said first or said second wavelength (λ 1 , λ 4 ), respectively, - the second image-generating unit is configured to generate a light beam in a wavelength band (Δλ) that contains said second or said first wavelength (λ 1 , λ 4 ), respectively, and - said spectrally selective optical filter is configured to transmit or reflect, respectively, light in most of said wavelength band (Δλ), - the first image-generating unit comprises at least one monochromatic light source , which emits only at said first or said second wavelength (λ 1 , λ 4 ), respectively, - the second image-generating unit is configured to generate a light beam in a wavelength band (Δλ) that contains said second or said first wavelength (λ 1 , λ 4 ), respectively, and - said spectrally selective optical filter is configured to transmit or reflect, respectively, light in most of said wavelength band (Δλ), <EOS>