Use TSL2561 and DS1307 RTC together
You can use the DS1307 itself just fine, but you are probably using a breakout board. These boards have (pull-up) resistors on it that will pull-up the I2C lines to 5v, while you only want 3.3v. This will not damage the arduino, but could damage chips like the  TSL2561, that can only handle 3.3v. 



On the board you indicated you are using, you need to remove R2 and R3

Other 5v sensor breakout might also have pull-ups to 5v. Easiest way to check, is to connect 5v and ground, and then measure the voltage on the SDA and SCL pins. If it's 5v, then it has pull-up resistors that need to be removed.