This is a 155 Schneider Howitzer being towed down the streets of McMinnville, Tennessee.
The Schneider 155mm (6.1 inch) howitzer was a French howitzer built from 1916 to 1918. The U.S. adopted the howitzer and it became the standard heavy howitzer for the U.S. The U.S. Army purchased 1503 of the howitzers from France and manufactured an additional 626 in the U.S. The U.S. version varied slightly from the French version. I believe the model in the picture is an upgraded 1917 model with rubber pnuematic tires and air brakes. However, it still possess the curved shield. The 1918 U.S. model had a straight shield.
The M1 155mm howitzer superseded the Schneider in 1942. However, the Schneider was used throughout WWII by both the U.S. Army and Marine artillery units.