“I am still speechless about what happened on Friday,” the 31-year-old wrote on both his Facebook and Twitter accounts.
“My sincerest condolences to everybody who is affected by this terrible tragedy.
“My prayers also go out to all the people who lost their lives the day before in Beirut.
“No matter where you come from and what religion you follow – we are united.”
The Manchester United midfielder captained Germany against France on Friday in a friendly which was overshadowed when at least 129 people were killed in a series of violent terrorist attacks across the French capital.
Several deaths took place near Paris' Stade de France where the friendly international took place.
The fearful German team preferred to spend Friday night at the stadium than drive across the city, the squad attempting to grab some sleep on mattresses on the changing room floor, before flying home early Saturday.
Last Thursday, twin bombing attacks in Beirut killed 44 people and at least 239 people were wounded in the blasts in a busy shopping street.
The Beirut attacks were later claimed by the Islamic State extremist group.
Schweinsteiger is set to wear the captain's armband again on Tuesday with the Germans due to host Holland in Hanover while the French Football Federation has said their friendly against England at London's Wembley will go ahead.