The phrasing is that much more confusing because France is a long scale country, so "one thousand trillion" is the valid way to say 10^21. If 1 byte = 1 metadata element (unlikely), that's a zettabyte. Which is probably not what's meant.
The headline of TFA's TFA (the source article) says
"La DGSE collecte ainsi des milliards de milliards de données".
That translates to 'millions of millions' pieces of data, or on the order of 10^12 (trillions in short scale) pieces of data.
eta: From the article: "capable of managing dozens of petaoctets of data, in other words dozens of millions of gigaoctets"
10^18 bytes in petabytes = 888.17 petabytes
or basically a million terabytes if you round up.
basically 3 million 1TB hard drives in raid 5 (1M x 3). you can probably fit a 500 1TB 2.5" drives into a single rack if you really try, and 2,000 racks can fit easily into warehouse-sized facility. (grid of 100 x 20 racks)
A milliard is a billion.