signed and dated 'Mathieu 69' lower right; titled '"PRITZ"' on the reverse watercolour, ink and red felt collage on paper 55.3 x 76.4 cm (21 3/4 x 30 1/8 in.) Executed in 1969, this work is accompanied by a certificate of authenticity signed by Édouard Lombard and dated 31 August 2017.