See below. If your Maurice Colbert was a tailor then he WAS the one living at 311 1st AVENUE as Dan found in the Naturalization Index dated Oct 16, 1856. The index page also shows the witness was John Coffey of 158 Maiden Lane.
Manhattan city directory: 1852: Colbert Maurice, tailor, 304 Av 1 1853: Colbert Maurice, tailor, 311 Av 1 1854: Colbert Morris, tailor, h. 311 First av 1856: Colbert Maurice, tailor, h. 311 First av.
There aren't any other Maurice or Morris Colberts in the directory over these years to muddy things.
1852 is the first time Maurice Colbert appears in the directory.