Forex brokers that control scalping and apply restrictions based on scalping activity

ActivTrades - micro-lot trading service may not be compatible with all scalping techniques, and may therefore be temporarily or permanently removed from the concerned accounts after proper notification. Scalpers are welcome to trade on Interbank accounts. 
AFX Capital - scalping is allowed on EA scalping accounts. 
AGEA - the maximum number of short-term positions (shorter than 5 minutes) a trader can have in a 4-hour period is 10. If a trader closes more than 50 short-term positions or more than 200 total positions in 7 consecutive days, the trader's account will be temporarily prevented from sending new orders into the market.
AJAJ Group - scalping is allowed, but monitored. 
AL Trade - we consider scalpers somebody who systematically pip hunts below 2-5 pips on average. Since it is difficult to cover such positions in the market, we would need to increase the spreads or apply trading limits for clients with permanent scalping strategies. Accordingly spread and order levels will be increased on your trading account according to Article 3.5 of AL Trade Customer Agreement Annex B. 
Alpha Capital Markets - scalping is allowed, but monitored. 
Bulls And Bears Forex - scalping is allowed, but monitored, and traders can only do scalping if they choose a Scalping Account. 
C.I.M. Banque - we have no problem with scalpers as we do have a huge liquidity. However, above a "5 million transaction", we would prefer to talk to you before to understand exactly how you work. 
CMC Markets - don't totally restricts, but actively discourages scalping. 
CommexFX - scalping allowed, but is monitored. 
CornerTrader - scalping is allowed, but is monitored. 
Easy-Forex - Time limit for closing positions is 30 seconds. 
eToro - minimum time to stay in a trade is 5 minutes. 
FIBO Group - allows the use of scalping, unless your strategy does not breach trading rules of the company. 
Finotec Trading Inc - scalping is possible, but not entirely tolerated. 
Forex Club Financial Company - scalpers requesting many of quotes without executions will be put you on the bottom of the list and receive lesser priority.
GKFX - scalping is allowed, but monitored. 
HY Markets - scalping is allowed but it is monitored. 
IBFX - will notify a trader if scalping went too far. 
ICM Capital - scalping allowed, but monitored. 
InstaForex - P. 3.14.6. Orders that have not more than 2 minutes left before being closed (or the time left before a lock order is executed) can be canceled by the Company. 
InvestTechFX - Scalping account available for day trader with high level of activities and above monthly customers average trading. Minimum Fee of $10 per Lot applies. 
FXOpen - you can scalp but most of your positions should open for at least 1 minute. 
IKOFX - Scalping techniques less than two minutes are prohibited, all trades are required to be held at least two minutes or longer. Penalty may cause profits and rebates to be forfeited. 
Nexsus Financial Markets - scalping is allowed, but is monitored. 
One Financial Markets - scalping is allowed, but it's monitored. 
PFG FX - Pro Finance Group - You may get the requotes when scalping. 
Price Markets - scalping is allowed on Dynamic MT4 & ECN accounts only. 
Profiforex - scalping is allowed, but it's monitored. 
Real Trade - Market orders closed in a 60 second period (or before the 5th tick) from the moment of opening an order are subject to cancellation. Orders longer that 1 minute are fine. 
RPD FX - scalping is allowed, but is monitored. 
UPME Group - scalping is allowed, but it is monitored. 
Windsor Brokers - at Windsor we tend to give our client to use the trading strategies that suits their need and if the client trading strategies is considered inappropriate our unprofessional the client is officially advised before taking any action concerning his account. 
XForex - There must be at-least 1 pro-mile difference between stop loss and profit target to the current market rate. 2 minutes must pass before trader can close deal.