PSG qualified for the knockout stage placing second in Group F, while an unbeaten Sociedad topped Group D.
"I'm pleased with the draw because I really wanted to go back to Spain," the former Barcelona and Spain coach told reporters on Tuesday.
"We know Real Sociedad really well. They have lots of players who have been with Spain, in the national team with me.
"We know it will be difficult. They won a group that included Inter Milan who were finalists in the championship last season. And they still managed to finish top."
Luis Enrique, who joined PSG in July, said he was still in the process of improving the squad to get the best out of them.
"I am very pleased with the first half of the season in terms of results," he said.
"We had such a difficult Champions League group. And in the end, we've had good results also in the league.
"The most difficult part is still to be done in the second half of the season."
PSG have a five-point lead at the top of the Ligue 1 standings and face 14th-placed Metz on Wednesday. However, Luis Enrique warned his side not to be complacent against their opponents, who are coming off three straight losses.
"It will be a really difficult game... they will leave us with very little spaces to attack," he said.
"We will need to be very precise and accurate to exploit those spaces."
The matchday will coincide with the birthday of Kylian Mbappe who has scored 164 league goals for PSG, including 16 this season from 15 appearances.
"Kylian Mbappe is still very young at 25. He is the age of my son which is quite something," Luis Enrique said.
"I hope that Kylian Mbappe achieves so much more success both collectively and individually. We hope that will be here at PSG and we hope to help him develop."
