Do I need a Schengen visa to transit Amsterdam and Paris enroute to Lagos from U.K [duplicate]

Amsterdam to Paris is an intra-schengen flight so yes you definitely need a schengen visa and not just a transit visa but a full Schengen visa. You need to be admitted into the Schengen area before you can board such a flight. The very point of the Schengen area is that in a typical case (these days, not always) after disembarking from a plane you do not need to go through any passport checks significantly speeding up the process (and offloading the immigration staff at the destination airport).