The government awarded a $23.8 million contract for the construction of the world's longest escalator Friday to a joint Hong Kong-French venture.

The new firm PYSOGEA, comprising Paul Y. Construction of Hong Kong and Sogea, a French company, said it planned to begin construction in March with completion scheduled for mid-1993.The 874 yards of moving sidewalks and automatic staircases is planned to wind through the British colony's congested central business district into a booming residential area popular with mid-level executives.