The One Direction star was arrested following the incident at Los Angeles International Airport on March 3, when he was travelling with his girlfriend Eleanor Calder.
A spokesman for the Los Angeles City Attorney's Office said on Monday: "No decision has yet been reached in that matter. It is still under review.
"Our office has up to one year to file charges from the original incident."
The case was due to be heard at LAX courthouse on March 29 but the hearing was postponed.
Tomlinson and Calder had been returning to Los Angeles after a holiday in Las Vegas when he allegedly clashed with a photographer, named in reports as Karl Larsen.
Lawyers for the 25-year-old singer said he was "provoked" by the paparazzi during the incident, while Calder is believed to have argued with onlookers who began filming the row.
An arrest record showed Tomlinson was held under citizen's arrest and the alleged offence was classed as a misdemeanour.
After the incident, Tomlinson's lawyer Martin Singer said: "The paparazzi provoked and caused the altercation that occurred with Louis at the airport.
"This is not the first or last time that a paparazzi has created an altercation with a celebrity.
"While the altercation was going on with the paparazzi, three other individuals were attacking his girlfriend during this incident and he came to her defence."
Bail was set at 20,000 dollars (£16,000) at the time of Tomlinson's arrest.
A source revealed the singer did not have to pay the amount because he was released under his own recognisance, meaning he had pledged in writing to appear in all court proceedings.