No. The I3C CCCs are always preceded by I3C Broadcast Address, 7’h7E. Since the I2C specification reserves address 7’h7E, no legacy I2C Slave will match the I3C Broadcast Address, and thus would not respond to the I3C commands. Likewise, the Dynamic Addresses assigned to I3C Devices would not overlap the I2C static addresses, so an I2C device would not respond to any I3C address (even if it could see it).

FAQ Type: 
I3C