The two matches in question were Leicester's Champions Cup game against Toulon in December and a Premiership meeting with Newcastle in March.
"This is the first such case that we know of in rugby union and is certainly the first brought under the relatively new Regulation 17 so this is new ground," RFU disciplinary panel chairman Christopher Quinlan said in a statement.
"In arriving at the appropriate sanction we have been careful to remind ourselves that we must not make an example of Phil Blake," added Quinlan.
"We have imposed a sanction which we consider fair and proportionate to what he did while having due regard to the proper consideration of deterrence."
Blake was also fined 669 pounds ($1,052), the profit made on the bets placed, and an appeal against the length of his ban was dismissed.
(Reporting by Ed Osmond, editing by Tony Jimenez)
