以次充好

yǐcìchōnghǎo
  1. (Mainland China, law) to replace genuine products with substandard ones
  2. to replace genuine products with substandard ones

Wiktionary

Entry Composition

1 以次 yǐcì
  1. in the proper order
  2. the following
2 充好 chōnghǎo to substitute shoddy goods