It depends on the size of the person and table, but for a full grown man of a full-sized table, you need about 7 x 8 foot (215 x 245cm). For children and smaller table, this will be reduced. Read more below
Is My Room big enough for a foosball table?
If you have a full-sized foosball table in a room, you will need the space shown in the diagram below. If you do not have enough space and decide on a smaller table, you are only saving the space of the table. The player remains the same size. You can only save a few inches!
Children are smaller and require less space, but they grow quickly, so try not to make it too cramped for them, otherwise in 6 months they will not fit!