DANDONG, China — Along the Chinese border with North Korea, the evidence of Beijing’s leverage in the coming talks between President Trump and the North Korean leader, Kim Jong-un, is everywhere.

Footage of China’s president, Xi Jinping, hosting Mr. Kim this week plays in a loop on a big outdoor screen here in the city of Dandong, and residents are eager for cross-border trade to resume as sanctions on North Korea are eased. Traders say they are putting in advance orders for coal from North Korean suppliers. Some exporters are already smuggling goods across the border.

“If you bribe the customs officials twice as much as before,” said one businessman who sells machinery for mining, “some of the smaller equipment goes through.”

At a new apartment complex where four 15-story towers are going up, sales have taken off and prices have doubled as buyers — including North Koreans carrying stacks of Chinese currency — snap up studios overlooking the Yalu River, a saleswoman said.