Aside from the city's French influence, one of the biggest contributors to the international atmosphere is the NGO sector. Humanitarian aid workers produce a thriving sub-market for relaxed cafés serving fresh, organic foods. Some of the best restaurants in this category are actually operated through NGOs and give most (if not all) of their proceeds to local charitable causes.
Of course, a trip to Phnom Penh wouldn't be complete without a healthy dose of Khmer cuisine, and there's plenty to be had from local food stalls in the city center or along the river. Stir fries, noodles, curries and sticky rice are all on the menu.
All around Central Market (Psar Thmei) is a collection of bars, cafés and Chinese restaurants that are busy at all hours. Most of the restaurants tourists are likely to visit are found here, and they're easily accessible on foot from the main market area.
The Sisowatch riverside area, stretching out from the Royal Palace, has some of the best French restaurants in Phnom Penh. Most are housed in colonial-era mansions and are brimming with class and atmosphere. The riverside also hosts more than a few local food stalls serving excellent budget fare.
Cross the Friendship Bridge and follow Route 6A to reach this dining district. This is a favorite local haunt with roadside stands, drink kiosks and a few nightclubs that mainly serve Cambodian fare, though there are also a few Chinese eateries. The best way to get here is by taxi, and then it's a matter of following the crowd to the most popular establishments. This is a guaranteed good time for culture lovers.
Beng Keng Kang
A short distance north of the city center is Beng Keng Kang, a dining district that follows the Tonle Sap River. Tourists regularly travel to this area in order to visit the Genocide Museum and the Killing Fields, and the trendy and relaxed restaurants in this area cater to all tastes and are busiest during the day.